LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Class 


Deformations  of  Railroad  Tracks 
and  the  means  for  remedying  them 

by 

G.  CUENOT 

Chief  Engineer  of  Bridges  and  Highways 

Attached  to  the  Board  of  Control  of  the  Paris -Lyons -Mediterranean 
Railroad  Company. 


Authorized  Translation 

by 

W.  C.  GUSHING,  M.A.,  B.S. 

Chief  Engineer  of  Maintenance  of  Way 

Pennsylvania  Lines  West,  South-West  System. 


1907. 

THE  RAILROAD  GAZETTE 
NEW  YORK  :  83  Fulton  Street        CHICAGO :   Old  Colony  Building 

THE  RAILWAY  GAZETTE 
LONDON:   Queen  Anne's  Chambers,   Westminster,  S.  W. 


Copyright,  1907, 

by 
THE  RAILROAD  GAZETTE. 


To  Mr.  Noblemaire,  the  Eminent  Director  of  the  P.   L.  M.  Co. 

I  have  the  honor  of  respectfully  dedicating  this  study,  in 
recognition  of  the  very  courteous  reception  which  I  have  met  with 
among  the  employees  of  the  company,  and  of  the  kind  accommoda- 
tion which  Messrs.  Rascol,  Chief  Engineer  at  Lyons,  and  Ferry, 
Sub-Engineer  at  Bourg,  have  always  accorded  to  me. 


174377 


OF  THE 

I    UNIVERSITY   ) 

OF 


AUTHOR'S   PREFACE. 

It  is  evident  that  railroad  travel  is  about  to  undergo  a  consid- 
erable evolution.  Speeds  of  100  and  120  kilometers  (62.14  and  74.52 
miles)  an  hour,  which  were  considered  as  maxima,  have  been 
exceeded,  by  reason  of  continual  progress  which  has  been  realized, 
and  which  permits  a  better  utilization  of  energy;  we  actually  talk  of 
engines  capable  of  traveling  at  a  speed  of  200  kilometers  (124.27 
miles)  per  hour.  Some  experiments  have  been  lately  made  in 
Germany  on  this  subject;  a  speed  of  200  kilometers  has  been  easily 
attained,  but  it  was  necessary  to  reduce  it,  in  spite  of  all  precau- 
tions taken,  because  the  track  was  not  in  a  condition  for  support- 
ing the  forces  of  all  kinds  which  were  developed  under  the  influence 
of  such  a  speed. 

The  problem  which  is  proposed  is  comparable  to  that  of  design- 
ing armor-plate  capable  of  resisting  the  shocks  of  projectiles.  When 
the  armor-plate  has  been  found,  we  are  forced  to  produce  a  pro- 
jectile more  powerful,  and  then  the  armor-plate  has  to  be  reinforced. 
This  quasi  duel  between  two  contrary  objects,  the  armor  and  the 
projectile,  will  always  be  pursued;  the  advantage  of  one  will  soon 
be  balanced  by  the  progress  of  the  other,  so  that  we  can  never  know 
which  is  master.  The  same  principle  holds  true  in  the  case  of 
train  movement,  the  speed  of  which  should  necessarily  increase,  while 
at  the  same  time  we  must  acquire  more  complete  mastery  of  the 
energy  that  creates  speed.  But  progress  in  locomotive  design  is 
restricted  by  the  limitations  of  the  structure  which  carries  the  load. 
We  shall  only  be  able  to  fully  profit  by  the  first  after  we  have  per- 
fected the  second. 

The  support  of  the  engine  comprises,  apart  from  the  roadbed, 
the  ballast,  the  ties  and  the  rails.  It  must  .be  made  more  resistant 
by  consolidating,  by  rendering  more  rigid,  the  elements  which  com- 
pose it,  for  it  is  very  evident  that  if  these  elements  are  susceptible 
of  rendering  good  service  when  they  are  submitted  to  given  forces, 
they  will  not  necessarily  continue  to  do  so  when  these  forces  are 
increased,  either  by  weight  of  load  carried  or  by  speed  of  trains  run. 

The  time  seems  to  have  come,  therefore,  for  making  a  minute 
study  of  the  track,  to  ascertain  what  forces  it  is  subject  to,  and  how 


ii 

it  can  be  made  stronger.  These  forces,  however  great  they  may  be, 
are  generally  created  as  the  effect  of  a  continuous  series  of  slight 
movements — the  creeping  of  rails,  inward  inclination  of  rails,  bend- 
ing of  the  ties,  pulling  of  spikes,  etc. — movements  which  have  not 
always  received  the  attention  they  deserve.  These  effects  are  pro- 
.duced  slowly,  successively,  in  such  manner  that  the  final  result  is 
not  very  apparent,  and  that  one  often  neglects  to  observe  the  cause 
and  explain  it.  For  example,  it  is  admitted  that  rails  creep  in  the 
direction  of  the  travel  of  the  train,  the  left  rail  more  rapidly  than 
the  right  one;  nevertheless,  certain  companies  maintain  that  this 
movement  has  never  been  proved.  Is  is  not  rather  true  that  the 
time  has  never  been  taken  to  observe  it?  But  this  slow  creeping  is 
important  by  its  repetition;  it  produces  a  skewing  of  the  ties,  and 
allows  the  rail  to  escape  from  its  fastenings,  and  is  the  cause,  con- 
sequently, of  high  maintenance  expenses.  In  like  manner  investi- 
gation has  not  yet  been  made,  at  least  to  our  knowledge,  of  the  cause 
of  the  more  rapid  creeping  of  the  track  to  the  left  than  to  the  right. 
Numerous  reasons  have  been  given,  such  as  the  lack  of  symmetry 
of  the  engine,  the  position  of  Giffard,  etc.,  but  they  have  never  been 
fully  elucidated. 

The  problems  of  tie  flexure  of  the  length  to  be  given  ties  in 
order  to  produce  the  least  deformation,  have  been  the  object  of  very 
little  research,  at  least  in  France.  We  are  contented  with  con- 
tinuing the  laying  and  the  maintenance  of  track  with  the  same 
information  and  the  same  methods.  These  methods  are  certainly 
not  bad,  since  they  have  permitted  the  operation  of  the  railroads, 
after  the  manner  with  which  we  are  familiar,  to  general  satisfac- 
tion. But  if  traffic  is  going  to  be  moved  more  rapidly  without 
lessening  the  degree  of  safety,  these  methods  are  going  to  prove 
unsatisfactory.  There  is  no  doubt  that  we  can  have  much  higher 
speeds  than  those  to  which  we  are  accustomed,  but  the  track  as 
now  constituted  is  not  strong  enough  to  carry  them. 

I  have  had  the  good  fortune,  since  the  commencement  of  my 
career,  to  be  occupied  with  railroad  questions,  and  for  the  five  years 
that  I  have  been  attached  to  the  service  of  the  Board  of  Control 
of  the  P.  L.  M.  Co.,  I  have  studied  these  questions  for  myself; 
making  frequent  journeys  on  foot,  watching  trains  pass,  and  noting 
all  which  appeared  to  me  interesting.  I  have,  moreover,  conversed 
with  many  trackmen,  and  have  often  seen  the  justice  in  their 
observations. 

In  the  present  study  I  shall  summarize  information  obtained  in 
such  conversation — information  difficult  to  obtain  from  any  but 


iii 

direct  sources.  I  am  inclined  to  mistrust  general  inquiry  made  by 
writing;  it  usually  produces  no  result,  unless  care  is  taken  to  dis- 
tinguish information  obtained  from  conscientious  employees  from 
that  which  comes  from  the  less  careful  ones,  the  latter  having  the 
tendency  to  substitute  their  opinion  for  the  actual  facts.  Both  types 
of  employees  are  capable  of  being  useful  in  practical  service,  but 
ara  not  equally  endowed  with  the  critical  spirit  and  the  spirit  of 
observation.  This  sense  is  quite  rare,  and  if  the  critic  does  not  suc- 
ceed in  distinguishing  it,  he  finds  himself  in  the  presence  of  informa- 
tion so  contradictory  that  he  does  not  know  how  to  draw  from  it 
what  is  useful. 

It  is  also  necessary  to  request  observations  from  employees 
who  have  apparatus  for  measuring,  and  "who  have  placed  bench 
marks  in  their  district,  enabling  them  to  fix  in  plan,  as  in  eleva- 
tion, the  points  which  they  designate.  A  simple  estimate  by  an 
employee,  however  intelligent  he  may  be,  is  never  worth  as  much 
as  a  figure,  or  a  fact  well  determined  and  met  with  a  great  number 
of  times.  I  will  give  an  example,  of  which  I  have  lately  been  a 
witness.  A  track  employee,  questioned  by  one  of  his  chiefs  on  the 
length  to  be  given  to  the  tamped-bed  of  a  tie,  replied,  without  hesi- 
tation: "The  best  length  is  25  centimeters  (9.84  in.)  on  both  sides 
of  the  rail."  This  reply,  made  with  great  authority,  would  seem 
to  be  peremptory.  After  the  experiments  which  I  had  had  made,  it 
seemed  to  me,  however,  so  badly  founded  that  I  made  an  investiga- 
tion. I  found  out,  with  certainty,  that  in  this  man's  district  not  a 
single  tie  was  tamped  to  the  amount  specified — a  fact  not  occasioned 
by  the  ill-will  of  the  trackman,  but  because  this  tamped-bed  could 
not  be  practically  realized,  as  I  will  show.  This  employee  had 
simply  expressed  his  personal  idea,  and  made  his  chief  believe,  by 
the  assurance  with  which  he  gave  it,  that  such  a  tamped-bed  was 
possible.  Other  employees  present  at  the  conversation,  less  positive 
because  they  were  more  careful,  spoke  of  35  centimeters  (13.78  in.) 
or  40  centimeters  (15%  in.);  they  were  nearer  the  truth.  It  is 
evident  that  no  useful  opinion  could  be  found  from  such  contra- 
dictory statements  of  fact,  unsupported.  Exact  evidence  is  not  hard 
to  get;  but  here  again  it  is  a  mistake  to  be  satisfied  too  soon,  and  it 
must  be  remembered  that  every  track  foreman  has  his  own  methods, 
founded  on  experience  rather  than  on  rule.  It  is  certainly  difficult 
to  make  rules  of  universal  application;  the  local  foreman  must  be 
allowed  some  latitude.  Tamping  varies  with  gravel  and  with 
broken  stone,  although  the  limits  of  variation  are  so  slight  that  they 
need  not  be  reckoned  here. 


iv 

In  discussing  the  tamping  of  ties  in  the  ballast  I  shall  not 
content  myself  with  presentation  of  statements  or  opinions,  but  will 
show  facts  developed  under  my  own  supervision,  since  one  is  best 
qualified  to  speak  of  the  things  that  he  has  seen  himself.  I  have 
been  able  to  make  a  large  number  of  such  observations,  and  collect 
a  great  many  instances  for  comparison,  especially  as  regards  ties. 
Apart  from  the  ordinary  wood  tie,  I  have  also  experimented  with  a 
steel  and  wood  composite  tie,  and  with  the  steel  tie  employed  on  the 
State  System  of  France.  From  comparisons  thus  obtained  I  have 
been  able  to  deduct  precise  rules  which  I  would  certainly  not  have 
been  able  to  do  by  working  in  any  other  manner. 

It  must  be  kept  in  mind  that  a  similar  study  has  been  previously 
made  in  France  by  engineers  of  the  highest  repute,  Messrs.  Coiiard 
and  Freund.  The  studies  which  I  have  pursued  have  confirmed 
and  made  exact  the  results  obtained  by  these  engineers.  If  I  have 
been  able  to  go  further  than  they,  and  to  present  firmer  conclusions, 
it  is  because  I  have  had  at  my  disposal  means  of  comparison  which 
they  lacked,  but  I  have  entirely  verified  the  exactness  of  the  obser- 
vations which  they  have  made,  and  I  appreciate  fully  the  conscien- 
tious work  which  they  have  done. 

I  have,  therefore,- confined  myself  to  the  experimental  method 
supplemented  by  explanations  derived  by  calculation  from  experi- 
mental data.  This  is  the  opposite  method  to  that  employed  by  the 
German  engineers,  Messrs.  Winckler,  Ast  and  others,  who  have 
started  from  hypotheses  not  verified  by  experiment  and  have 
deduced  facts  from  them  by  calculation,  which  they  have  taken  as 
established  without  discussion.  They  have  even  subordinated  obser- 
vations based  upon  experiment  to  the  results  of  such  calculation, 
and  have  not  hesitated  to  conclude  that  these  observations  could  not 
be  exact,  since  they  diverged  from  the  calculated  results.  I  believe 
that  this  method  can  produce  nothing  useful,  but  that,  on  the  con- 
trary, by  rejecting  conscientious  experiments,  it  ends  in  false  con- 
clusions. Results  based  on  hypotheses,  however  ingenious  they  may 
be,  can  have  no  more  value  than  the  hypotheses  from  which  they 
are  derived.  Moreover,  the  study  of  track  is  an  extremely  complex 
thing;  the  reactions  of  the  sub-soil,  ballast,  ties  and  rails  are  many 
and  confusing,  and  they  become  complicated  with  each  other  and 
distorted  to  such  a  degree  that  they  cannot  be  expressed  in  terms  of 
simple  relation. 

To  co-ordinate  observations  which  I  have  myself  gathered;  to 
see"k  to  derive  a  law — not  a  mathematical,  but  physical — which 
binds  them  up  together  as  well  as  possible;  this  is  the  end  which 


1  have  in  view.  To  supplement  this,  it  is  only  necessary  to  follow 
the  instructions  given  by  Mr.  Coiiard  in  his  very  interesting  studies 
of  track,  known  to  all  who  occupy  themselves  with  this  subject. 

I  wish  also  to  state  that  I  have  been  very  earnestly  aided  by  the 
engineers  and  employees  of  the  P.  L.  M.  Company,  all  carefully 
selected  men,  notably  by  Mr.  Ferry,  Assistant  Engineer  at  Bourg, 
who  is  endowed  with  unusual  powers  of  observation.  For  nearly 
forty  years  Mr.  Ferry  has  accumulated  facts;  not  merely  superficial 
observations  which  serve  only  to  confuse,  but  careful  results  which 
make  it  possible  to  supply  figures  and  instances  to  the  support  of  an 
opinion.  I  have  the  greatest  desire  to  continue  the  study  of  these 
track  deformations,  themselves  almost  infinitely  small,  but  having 
an  effect  comparable  to  that  of  tiny  microbes  on  the  human  organ- 
ism. At  this  time,  when  it  is  imperative  that  track  should  be  made 
more  rigid  to  respond  to  new  traffic  conditions,  this  branch  of  study 
increases  in  importance,  and  will  alone  furnish  a  means  of  com- 
bating these  small  movements  of  the  track  which,  isolated,  are  of 
small  importance,  but  with  sufficiently  frequent  repetition  disor- 
ganize the  carrying  power  of  railroad  superstructure. 

I  do  not  pretend  in  the  present  work  to  have  studied  completely 
these  movements.  I  realize  that  there  is  yet  much  to  do,  and  I  shall 
be  extremely  glad  if  others,  still  better  fitted  than  I  am,  shall  become 
interested  in  continuing  this  study  and  in  adding  a  new  collection 
<of  observations  to  those  which  I  have  made. 

G.  CUENOT. 


TRANSLATOR'S  PREFACE. 


The  question  of  the  proper  length  to  be  given  to  cross  ties 
has  been  before  the  American  Railway  Engineering  and  Main- 
tenance of  Way  Association  for  the  past  two  years,  and,  doubtless, 
the  same  question  ha?  been  presented  to  maintenance  of  way 
officers  by  the  managers  of  their  companies  in  the  hope  of  buying 
at  less  cost  an  article  of  supply  which  is  ever  increasing  in  price, 
and  at  the  same  time  is  such  a  necessary  part  of  the  construc- 
tion of  a  railroad. 

Up  to  the  present  time,  the  problem  has  not  been  very  scien- 
tifically treated  in  the  United  States,  and  there  is  some  divergence 
of  opinion  relative  to  the  matter,  usually  based  on  the  practice 
under  which  the  individual  expressing  it  has  grown  up. 

Upon  reading  the  account,  therefore,  of  Mr.  Cuenot's  painstaking 
experimental  work,  it  occurred  to  the  translator  that  the  descrip- 
tion and  results  would  be  interesting  to  the  English  speaking 
engineers  who  are  occupied  with  such  questions  in  their  own  work, 
and  he  therefore  made  arrangements  with  the  author  for  intro- 
ducing the  work  to  them.  The  author  has  been  very  kind  and  lib- 
eral in  the  transaction,  by  reason  of  his  truly  professional  and 
scientific  spirit,  and  the  translator  takes  this  opportunity  for  ex- 
pressing his  appreciation. 

American  engineers  can  learn  a  lesson  for  themselves  from  the 
scientific  spirit  and  great  care  with  which  their  foreign  colleagues 
attack  a  problem  to  be  solved  and  carry  on  the  work  of  investiga- 
tion and  experiment. 

W.  C.  GUSHING. 


OF  THE 

UNIVERSITY 

OF 


Track  Deformations  and  Their  Prevention. 


CHAPTER  I. 

NATURE  AND  OBJECT  OF  EXPERIMENTS. 

The  Minister  of  Public  Works  expressly  charged  me  with  ex- 
perimenting with  a  composite  cross  tie  (wood  and  steel),  and  to 
make  him  a  report  on  the  result  of  the  experiments.  I  did  not 
believe  that  it  was  sufficient  to  place  a  cross  tie  in  the  track  and 
to  observe  the  manner  in  which  it  behaved.  It  seemed  to  me  that, 
in  order  to  discuss  with  some  competence  the  results  of  the  experi- 
ments, it  was  necessary  to  examine  what  takes  place  in  the  case 
of  a  normal  track  provided  with  ordinary  cross  ties  or  with  steel 
cross  ties  employed  on  the  State  System,  and  to  compare  the  results 
obtained  with  those  which  were  found  in  the  case  of  the  same  track 
provided  with  composite  cross  ties. 

It  was  a  question  then  of  a  collection  of  tests  bearing  on  all 
the  movements  to  which  the  track  is  submitted,  and  of  the  study 
of  all  the  deformations  to  which  it  is  subjected.  The  manner  in 
which  the  fastenings  behaved,  with  the  systems  tried,  ought  also 
to  have  my  attention;  it  was  interesting  to  give  an  account  whether 
or  not  the  methods  of  fastening  (employment  of  treenails)  would 
be  able  to  render  the  service  on  which  one  has  a  right  to  count. 
The  outline  of  the  study,  which  we  have  undertaken,  comprises 
nearly  all  the  questions  concerning  the  track,  including  the  joint, 
which  has  given  occasion  for  numerous  solutions. 

It  has  been  possible  up  to  the  present  time  to  study  the  influ- 
ence of  reinforcement  of  the  track  by  the  enlargement  of  section 
of  rails,  of  screw  fastenings,  and  of  rail  joints,  but  I  do  not  believe 
that  any  one  has,  up  to  the  present,  examined  the  influence  of  a 
stronger  section  given  to  the  cross  tie.  This  study  presented  then, 
apart  from  the  special  mission  which  had  been  intrusted  to  me, 
a  general  interest  which  I  immediately  recognized,  and  which  will, 
without  doubt,  justify  the  relatively  important  work  which  I  have 
done. 


TRANSLATOR'S  PREFACE. 


The  question  of  the  proper  length  to  be  given  to  cross  ties 
has  been  before  the  American  Railway  Engineering  and  Main- 
tenance of  Way  Association  for  the  past  two  years,  and,  doubtless, 
the  same  question  hap  been  presented  to  maintenance  of  way 
officers  by  the  managers  of  their  companies  in  the  hope  of  buying 
at  less  cost  an  article  of  supply  which  is  ever  increasing  in  price, 
and  at  the  same  time  is  such  a  necessary  part  of  the  construc- 
tion of  a  railroad. 

Up  to  the  present  time,  the  problem  has  not  been  very  scien- 
tifically treated  in  the  United  States,  and  there  is  some  divergence 
of  opinion  relative  to  the  matter,  usually  based  on  the  practice 
under  which  the  individual  expressing  it  has  grown  up. 

Upon  reading  the  account,  therefore,  of  Mr.  Cuenot's  painstaking 
experimental  work,  it  occurred  to  the  translator  that  the  descrip- 
tion and  results  would  be  interesting  to  the  English  speaking 
engineers  who  are  occupied  with  such  questions  in  their  own  work, 
and  he  therefore  made  arrangements  with  the  author  for  intro- 
ducing the  work  to  them.  The  author  has  been  very  kind  and  lib- 
eral in  the  transaction,  by  reason  of  his  truly  professional  and 
scientific  spirit,  and  the  translator  takes  this  opportunity  for  ex- 
pressing his  appreciation. 

American  engineers  can  learn  a  lesson  for  themselves  from  the 
scientific  spirit  and  great  care  with  which  their  foreign  colleagues 
attack  a  problem  to  be  solved  and  carry  on  the  work  of  investiga- 
tion and  experiment. 

W.  C.  GUSHING. 


Track  Deformations  and  Their  Prevention. 


CHAPTER  I. 

NATURE  AND  OBJECT  OF  EXPERIMENTS. 

The  Minister  of  Public  Works  expressly  charged  me  with  ex- 
perimenting with  a  composite  cross  tie  (wood  and  steel),  and  to 
make  him  a  report  on  the  result  of  the  experiments.  I  did  not 
believe  that  it  was  sufficient  to  place  a  cross  tie  in  the  track  and 
to  observe  the  manner  in  which  it  behaved.  It  seemed  to  me  that, 
in  order  to  discuss  with  some  competence  the  results  of  the  experi- 
ments, it  was  necessary  to  examine  what  takes  place  in  the  case 
of  a  normal  track  provided  with  ordinary  cross  ties  or  with  steel 
cross  ties  employed  on  the  State  System,  and  to  compare  the  results 
obtained  with  those  which  were  found  in  the  case  of  the  same  track 
provided  with  composite  cross  ties. 

It  was  a  question  then  of  a  collection  of  tests  bearing  on  all 
the  movements  to  which  the  track  is  submitted,  and  of  the  study 
of  all  the  deformations  to  which  it  is  subjected.  The  manner  in 
which  the  fastenings  behaved,  with  the  systems  tried,  ought  also 
to  have  my  attention;  it  was  interesting  to  give  an  account  whether 
or  not  the  methods  of  fastening  (employment  of  treenails)  would 
be  able  to  render  the  service  on  which  one  has  a  right  to  count. 
The  outline  of  the  study,  which  we  have  undertaken,  comprises 
nearly  all  the  questions  concerning  the  track,  including  the  joint, 
which  has  given  occasion  for  numerous  solutions. 

It  has  been  possible  up  to  the  present  time  to  study  the  influ- 
ence of  reinforcement  of  the  track  by  the  enlargement  of  section 
of  rails,  of  screw  fastenings,  and  of  rail  joints,  but  I  do  not  believe 
that  any  one  has,  up  to  the  present,  examined  the  influence  of  a 
stronger  section  given  to  the  cross  tie.  This  study  presented  then, 
apart  from  the  special  mission  which  had  been  intrusted  to  me, 
a  general  interest  which  I  immediately  recognized,  and  which  will, 
without  doubt,  justify  the  relatively  important  work  which  I  have 
done. 


±  TRACK  DEFORMATIONS. 

The  rails  employed  were  of  the  type  used  on  the  Paris,  Lyons 
&  Mediterranean,  either  the  P.  M.  type  of  a  weight  of  39  kilograms 
per  running  meter  (78.6  Ibs.  per  yd.),  or  the  P.  L.  M.-A.  type,  of  a 
weight  of  34 V2  kilograms  per  running  meter  (69.5  Ibs.  per  yd.). 

The  rail  joint  was  made  up  of  angle  bars.  The  screw  spikes, 
No.  6,  had  a  diameter  of  20  millimeters  (51/w  in.).  Between  the 
rails  and  the  cross  ties  are  metallic  plates  of  the  type  used  on 
the  P.  L.  M. 

All  my  experiments,  during  nearly  three  years,  have  been 
made,  first  on  a  side  track,  then  on  track  No.  2  of  the  line  from 
Mouchard  to  Bourg,  traversed  by  the  express  and  fast  trains,  com- 
paratively with  oak  cross  ties  employed  on  the  P.  L.  M.  system, 
and  with  composite  cross  ties  (wood  and  steel).  Finally,  a  special 
track  for  experiments  was  laid  at  the  Bourg  station,  and  there  was 
tested,  at  the  same  time  as  the  two  types  of  cross  ties  recited, 
the  metallic  cross  tie  in  use  on  the  State  System. 

But  before  making  inese  lesis  Known  it  is  essential  to  describe 
the  cross  ties  employed. 

The  wooden  cross  ties  of  wood  were  oak,  creosoted,  and  of 
the  following  dimensions: 

Length    2  m.  60  (8  ft.  6.36  in.) 

Width     0  m.  22  to  0  m.  25  (8.66  in.  to  9.84  in.) 

Depth    0  m.  14  to  0  m.  15  (5.51  in.  to  5.91  in.) 

Composite  cross  tie,  system  of  Devaux,  Michel  and  Richard. — 
This  is  composed  of  a  metallic  skeleton  in  the  form  of  an  inverted 
trough,  provided  in  .the  interior  with  two  symmetrical  blocks  of 
wood  solidly  fixed,  and  leaving  between  them  an  empty  central 
space. 

The  upper  surface  of  the  skeleton  presents,  on  removal  of 
the  track,  two  rectangular  openings,  leaving  exposed  on  the  blocks 
the  seatings  intended  to  receive  the  supporting  plates  for  the  rails. 
It  is  at  once  seen  that  this  plan  of  cross  tie  permits  the  use  of 
ordinary  screw  spikes  as  the  method  of  fastening  for  the  rails. 

The  metallic  skeleton  is  of  the  type  of  iron  section  known  in 
-commerce  under  the  name  of  Zores  iron,  as  the  section  AB  shows 
it.  The  trapezoidal  section  is  of  interior  dimensions: 

Width   at   base    0  m.  22     (8.66  in.) 

Width  at   top    0  m.  14     (5.51  in.) 

Depth    Om.  135  (5.32  in.) 

The  thickness  of  the  metal  ought  to  be  5  m/m  (13/64  in.)  but 
in  reality  it  is  only  4  m/m  %0  (3/16  in.),  and  the  total  length  is 
2  m  50  (8  ft.  2.4  in.).  In  later  experiments  the  length  was  reduced 
to  2  m  20  (7  ft.  2.64  in.).  The  side  walls  terminate  in  a  flange 


pel 

Z^TT 


4  TRACK  DEFORMATIONS. 

along  the  lower  edges.  The  object  of  this  arrangement,  which  is 
found  in  the  greater  number  of  metallic  cross  ties,  is  to  render  the 
cross  tie  better  able  to  resist  the  blows  of  tools  during  tamping, 
to  increase  the  moment  of  inertia  in  the  vertical  direction,  and 
also  to  permit  the  clamping  of  the  cross  bars. 

The  metallic  skeleton  is  provided  in  its  lower  part  with  four 
cross  bars,  two  under  each  block.  These  cross  bars  are  fixed  with- 
out bolts  or  rivets,  their  extremities  are  simply  curved  and  clamped 
on  the  flanges  of  the  skeleton.  Their  object  is  to  hold  together 
the  side  walls  of  the  metallic  envelope,  and  to  thus  insure  the 
wedging  of  the  blocks  in  the  interior  of  this  envelope.  The  metal- 
lic part  weighs  about  60  kilograms  (132.28  Ibs.). 

Each  wooden  block  is  composed  of  three  wedges  joined  to- 
gether, whose  dimensions  are  given  by  the  sections  AB  and  CD. 

The  rails  are  fixed  on  the  blocks  through  the  intermediary  of 
a  plate  with  shoulder,  by  means  of  ordinary  screw  spikes.  The 
supporting  surface  of  the  plate  is  inclined  at  l/m  in  order  to  give 
the  desired  inclination  to  the  rail,  and  the  mortise  is  made  in  such 
a  way  that  the  plate  should  be  well  supported  on  the  exterior  side 
of  the  track  by  the  corresponding  edge  of  the  notch  in  the  metallic 
skeleton  in  order  to  oppose,  in  case  of  need,  all  lateral  movement. 
The  object  of  this  arrangement  is  to  prevent  the  spreading  of  the 
track,  to  which  there  is  a  tendency  on  curves. 

The  heads  of  two  screw  spikes  of  each  middle  wedge  press  the 
rail  on  the  cross  tie,  and  ought  to  act  strictly  as  an  adjusting  screw 
on  the  middle  wedge;  for  this  effect  a  play  of  about  10  m/m 
(?y«  in-)  is  taken  up  between  the  upper  face  of  the  wood  and  the 
bottom  of  the  metallic  skeleton. 

This  arrangement  allows  a  strong  pressure  of  the  lateral 
wedges  against  the  sides  of  the  skeleton  to  be  obtained,  a  pressure 
which  the  passage  of  trains  only  increases  by  reason  of  the  reaction 
of  the  ballast,  which  tends  to  push  up  the  blocks  and  press  them 
against  the  lateral  walls. 

The  three  wedges  as  a  whole  form,  under  pressure,  a  true 
block,  solidly  maintained  by  the  metallic  skeleton  and  the  cross 
bars,  and  under  which  one  can  tamp  as  under  a  wooden  cross  tie. 

It  has  been  recognized  in  the  course  of  experiments  that  the 
wooden  part  was  like  a  monolith;  that  the  middle  wedge  once  in 
place  could  no  longer  be  pushed  up,  which,  upon  the  whole,  is  an 
advantage,  and  inventors  have  substituted  for  the  three  wedges  a 
single  wedge  pressed  into  the  skeleton  by  means  of  cross  bars, 
presenting,  besides  the  advantages  of  the  three-wedge  system,  a 


NATURE  AND-  OBJECTS  OF  EXPERIMENTS.  5 

better  supporting  surface  for  the  plate,  and  the  possibility  of  em- 
ploying the  chair  for  track  with  double  headed  rail.  This  latter 
system  offers,  besides,  easier  methods  of  manufacture. 

The  length  of  either  of  the  blocks  is  regulated  by  the  conditions 
under  which  they  distribute  the  pressure  on  the  ballast;  it  is  about 
0  m  70  (27.56  in.),  a  length  which  has  been  recognized  as  sufficient 
to  assure  the  bed  of  the  cross  tie  on  the  ballast. 

The  separate  wedges  of  the  blocks  are  cut  by  saw,  according  to 
patterns  made  with  care,  so  as  to  fit  exactly  in  the  interior  of  the 
skeleton. 

The  shoeing  (adzing  and  fastening  the  plates  to  the  ties)  can 
be  done  by  machine  by  previously  confining  the  blocks  in  a  special 
matrix,  which  will  hold  them  under  the  tools  of  the  planers  in  the 
desired  place  and  afterwards  serve  for  drilling  the  holes  for  the 
screw  spikes,  by  the  aid  of  augers  driven  by  steam. 

The  blocks  weigh  about  32  kilog.  (70.55  Ibs.),  and  the  weight  ot 
the  cross  tie  is  nearly  78  kilog.  (171.96  Ibs.). 

The  steel  cross  tie  used  on  the  State  System  is  also  shown  in 
the  section  herewith,  to  the  right  of  Zores  Iron.  It  is  2  m  50  (8  ft. 
2.4  in.)  long  and  weighs  58  kilog.  (127.87  Ibs.). 

The  various  characteristics  of  the  cross  ties  experimented  with 
are  summarized  in  the  table  on  the  following  page. 

The  composite  cross  tie  is  from  1^  to  3  times  as  rigid  as  the 
wood  cross  tie,  even  at  the  notches  prepared  for  the  seating  of  the 
tie  plates,  varying  according  to  whether  the  part  notched,  which 
is  the  weakest  section,  or  the  armored  metallic  part  is  considered. 
This  cross  tie  is  also  2  to  4  times  as  rigid  as  the  steel  cross  tie 
of  the  State  Railroads. 

It  is  possible  to  give  an  account  in  another  way  of  the  difference 
in  resistance  of  the  beams  considered.  In  fact,  if  the  condition  is 
imposed  that  their  deformation  be  the  same  for  a  like  force,  that 
is  to  say,  that  they  each  take  an  equal  elongation,  it  is  found,  by 
designating  L  this  elongation,  by  R,  R',  R",  the  stress  per  unit  of 
surface  of  these  beams,  E,  E',  E",  the  coefficient  of  elasticity  of  the 
material  of  which  they  are  made: 

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NATURE  AND  OBJECTS  OF  EXPERIMENTS.  7 

To  appreciate  the  difference  of  resistance  of  cross  ties  sub- 
mitted to  a  like  deformation,  it  will  be  sufficient  to  compare  between 

them  the  products  such  as  E-=-,  or  else,  if  the  resisting  moment 

h 

of  the   steel  beam  is   taken  for  a  term  of  comparison,  it   will   be 

I  E/ 

necessary  to  multiply  -=-  by   the  ratio  -=-.    The  following  results 

Lt  xL 

are  thus   arrived  at: 

Comparative  resisting  moments  of  different  cross  ties  supposed 
of  steel. 

Cross-tie  of  wood 36 

Composite  cross  tie  : 

In  the  armored  part    87 

In  the  middle  and  at  the  extremities 61 

Right  at  the  fastenings ' 60 

Steel  cross  tie  of  the  State 30 

The  part  of  the  metallic  skeleton  cut  out  to  permit  fixing  the 
fastenings  on  the  wooden  blocks,  which  is  necessary  for  the  placing 
of  the  plate,  or  the  chair,  is  of  short  length,  about  0  m  15  to  0  m  30 
(5.91  to  11.81  in.).  This  weakening  is  compensated,  and  more,  by 
the  plate,  or  chair,  which  forms  part  of  the  armored  beam. 

The  above  results  have  been  obtained  while  seeking  the  mean 
coefficient  E  of  the  armored  part  by  the  condition  El  =  2  ei,  E 
being  the  coefficient  of  elasticity  of  the  two  materials  considered,  I 
their  moment  of  inertia,  I  —  2  i;  and  the  neutral  axis  of  the  com- 
posite beam  being  determined  by  the  condition  that  each  element  is 
stressed  proportionately  to  its  coefficient  of  elasticity. 

The  composite  cross  tie  offers,  then,  in  all  its  sections,  a  resist- 
ance superior  to  that  of  the  steel  cross  tie  of  the  State;  it  will  then 
be  stressed  much  less  and  will  be  more  resistant,  under  much  more 
advantageous  conditions. 


EXPERIMENTS    OX    THE    SIDE    TRACK     AT    DOURO-EN-BRESSE. 

The  object  of  these  first  experiments  was  to  ascertain  the  sta- 
bility of  composite  cross  ties  and  observe  the  manner  in  which  the 
blocks  behaved.  It  was  essential  to  be  assured  of  these  two  points 
before  placing  them  in  a  main  track. 

The  metallic  skeleton  of  the  composite  cross  ties  was  made  of 
soft  steel  coming  from  dephosphorized  meltings,  and  its  form  ob- 
tained by  hammering. 

The  blocks  were  cut  with  a  saw  from  new  cross  tie  timber,  but 
from  waste  which  could  not  be  otherwise  utilized.  The  elements  of 
50  composite  cross  ties  were  thus  obtained;  46  were  made  of  oak 
J 


8  TRACK  DEFORMATIONS. 

and  4  of  beech.  The  wood  was  injected  with  creosote  at  the  work 
shop  of  the  P.  L.  M.  Co.,  at  the  station  of  Perrache  2. 

These  50  composite  cross  ties  were  placed  in  track  5  at  the 
station  of  Bourg-en-Bresse.  Their  spacing,  with  three  fastenings, 
two  were  exterior  and  one  interior,  was  one  meter  (39%  in.),  ex- 
cept at  the  joints  of  the  rails,  five  meters  long  (16.40  ft.),  where  the 
spacing  was  reduced  to  0  m  70  (27.56  in.)  and  0  m  60  (23.62  in.). 

This  laying  was  done  on  February  3,  1902,  at  a  period  little 
favorable  for  making  track.  The  earth  was  covered  with  snow,  and 
it  was  necessary  to  break  up  the  subsoil  in  order  to  proceed  with 
the  laying  of  the  experimental  cross  ties.  In  spite  of  these  unfa- 
vorable conditions,  it  was  only  on  the  13th  of  March  following  that 
the  first  repair  was  made,  consisting  of  a  general  tamping  necessi- 
tated by  the  thawing,  and  at  the  same  time  of  a  raising  of  all  the 
track.  Since  then  it  has  not  been  retouched. 

When  the  cross  ties  were  brought  to  their  place,  the  plate  was 
placed  above  the  blocks,  and  the  two  fastenings  of  the  central 
wedge  were  tightened  alternately  to  avoid  any  dislodgement  of 
that  piece. 

The  ballast  in  track  5  was  rough  gravel;  one  of  the  cross  ties, 
provided  with  two  sections  of  rail,  was  placed  apart  from  the  tracks 
in  broken  stone  in  order  to  see  in  what  fashion  the  pieces  of  wood 
would  behave  in  that  ballast.  The  metallic  skeleton  was  left  visible 
in  the  interior  of  the  track,  except  for  12  cross  ties,  which  were 
covered  by  ballast. 

From  the  time  of  their  placing,  the  cross  ties  were  subjected 
to  the  successive  effects  of  heavy  rains,  which  have  lasted  during 
the  greater  part  of  the  spring,  and  of  excessive  heat,  which  has 
ruled  during  the  summer. 

We  examined  at  different  visits  the  condition  of  the  track,  and 
found  each  time  that  the  condition  was  excellent;  that  notably  the 
fastenings  were  always  thoroughly  tight,  and  that  the  passage  ot 
the  heaviest  engines  (102.5  net  tons,  including  the  tender  and  the 
load  of  water  and  coal,)  did  not  cause  any  apparent  deflection  of 
the  metallic  part  binding  the  two  lines  of  rails. 

About  40  engines  per  day  passed  over  the  track,  which  repre- 
sents a  total  passage  of  1,200  per  month,  and  of  7,200  during  the 
six  months  of  experiments,  reaching  to  the  3d  of  August. 

Before  proceeding  with  the  experiments  on  the  resistance  of 
fastenings,  we  took  the  track  to  pieces  and  removed  some  cross 
ties.  We  found  that  the  tamped  bed  under  the  ties  was  absolutely 
intact;  that  the  wood  offered  no  trace  of  crushing,  and  that  the 


NATURE  AND  OBJECTS  OF  EXPERIMENTS. 


tightening  of  the  wedges  was. absolute;  that  the  central  wedge  had 
not  been  raised  by  the  tightening  of  the  screw  spikes,  and  that  the 
allowance  existing  after  placing  was  maintained  without  variation, 
as  is  shown  in  the  table  below: 

Interval  included  between  the  bottom  of  the 

plate  and  the  upper  face  of  the  wedge ^ 

?  axis— ^  /-To  left  of  axis.-^ 

Inch.        Millimeters.      Inch. 

Vs 

13/32 

18/32 

15/sJ 

10/32 

Vie 
Vie 

VJ/32 
15/32 
15/32 
21/32 

19/32 
15/32 
27/32 

»/» 

9/ie 

n/32 

The  composite  cross  ties  which  were  placed  at  the  Bourg  station 
were  replaced  in  the  month  of  January,  1903,  (from  the  5th  to  the 
8th)  in  compliance  with  the  ministerial  decision  of  December  12, 
1902,  in  track  2  of  the  line  from  Mouchard  to  Bourg*  between 
kilometers  494,417  and  494,465  in  proximity  to  the  station  of  Saint- 
Etienne-du-Bois,  above  an  embankment  of  argillaceous  nature,  about 
1  m  50  (4.92  ft.)  in  height.  This  part  of  the  line  is  located  at  the 
origin  of  a  curve  of  600  meters  (1,968%  ft.)  radius,  following  a 
tangent  alinement  of  6,604  meters  (21,666.6  ft.)  long,  at  the  extrem- 
ity of  a  series  of  grades  (4  m/m  6,  9  m/m  5,  2  m/m  8)  (0.47,  0.94, 
0.28  ft.  per  100),  which  follows  a  level.  It  resulted  from  this  situa- 
tion that  the  cross  ties  were  at  a  point  where  water  accumulates  and 
causes  the  ballast  and  the  embankment  on  which  it  rests  to  soften. 
The  ballast  came  from  the  Ambronay  quarries  (near  Ambe'rieu). 
It  was  composed,  like  the  greater  part  of  quarry  gravel,  of  silico- 
calcareous  gravel  and  of  loam  in  quite  a  large  quantity.  The  char- 

*This  line  is  used  by  fast  trains,  such  as  the  Berlin-Nice  and  the  Indian 
Mail ;  the  mean  density  of  traffic  of  this  line  is  about  20  trains  a  day  on  each 
of  the  tracks. 


Number 
of 
cross-ties. 
26 

,  plat 
r-To  rij 

Millimel 
3 

27 

28 
29 

15 
10 
6 

30 
31 

3 
10 

32 
33 
34 
35 

20 
12 
15 
8 

36 

5 

37 

38 

15 
12 

39 

12 

40 
41 

17 
16 

42 
43 
44 
45 
46 
47 
48 
49 

15 
12 
21 
16 
20 
16 
14 
9 

6 

1A 

12 

15/32 

10 

13/32 

5 

Vie 

10 

'13/32 

10 

13/32 

20 

25/32 

10 

13/32 

5 

Vie 

14 

Vie 

8 

Vie 

7 

%2 

14 

Vie 

12 

15/32 

16 

% 

22 

% 

13 

% 

17 

21/32 

18 

23/32 

19 

% 

18 

23/32 

17 

21/32 

18 

23/32 

17 

21/32 

10  TRACK  DEFORMATIONS. 

acteristic  of  this  ballast  is  to  form  a  conglomerate  very  hard  in 
dry  weather,  and  in  wet  weather  to  make  a  sort  of  mud  more  or  less 
fluid,  according  to  the  moisture  with  which  it  is  impregnated. 

The  cross  ties  were  placed  at  the  rate  of  12  cross  ties  per 
rail  length  of  8  meters  (26.25  ft.)  of  the  P.  M.  type,  weighing  39 
kilogs.  per  running  meter  (78.6  Ibs.  per  yd.),  over  4  lengths  of 
rail.  This  type  of  rail  was  chosen  because  the  width  of  its  base 
was  adapted  to  a  plate  whose  dimensions  were  precisely  thooe  of 
the  notch. 

The  rails  thus  employed  had  been  taken  from  the  track  after 
a  long  service*,  which  explains  their  exceptional  deformation  (see 
Fig.  3)  and  made  conspicuous  by  the  unevenness  of  3  millimeters 
(%  in.)  which  they  present  in  a  short  length  (about  1  meter) 
(39%  in.).  They  rested  on  the  cross  ties,  as  we  shall  see  further 
along,  by  means  of  P.  M.  plates;  the  fastenings  placed  unsymmet- 
rically,  and  composed  of  screw  spikes  No.  6,  were  to  the  number  of 
8  per  cross  tie,  2  outside  and  2  inside  each  of  the  rails.  There  was 
placed  at  the  beginning,  and  at  the  extremity  of  the  track  thus  laid 
on  composite  cross  ties,  a  length  of  rail  of  the  P.  M.  type  on  wood 
cross  ties  with  the  same  laying,  in  order  to  be  able  to  establish  a 
comparison. 

All  of  these  cross  ties  were  inclined  toward  the  center  of  the 
curve  of  600  meters  (1,968%  ft.)  radius  turning  to  the  right,  with 
a  superelevation  of  0  m  .083  (3Y83  in.).  This  inclination  had 
further  the  disadvantage  of  throwing  all  the  surface  water  of  the 
track  in  the  inter-track  space,  where  it  was  held  by  the  impermea- 
bility of  the  ballast. 

Left  under  these  conditions  for  more  than  a  year,  the  cross 
ties  have  been  submitted  to  the  successive  effects  of  heavy  rains, 
which  lasted  during  a  large  part  of  the  time,  and  of  the  period  of 
warm  weather. 

The  condition  of  the  track  was  examined  at  different  visits, 
and  it  was  proved  each  time  that  the  condition  was  excellent;  that 
there  was  never  occasion  for  retightening  the  fastenings,  and  that 
the  cross  ties  under  the  passage  of  trains  (about  8,000)  did  not 
undergo  any  apparent  bending.  Thus  there  was  placed  on  the 
composite  cross  ties,  the  same  as  on  the  neighboring  wood  cross 
ties,  *a  bed  of  gravel  over  the  whole  surface;  it  was  proved  that  not 
a  grain  of  gravel  was  detached  by  the  passage  of  express  train 
682  from  the  edges  of  the  composite  cross  ties,  whilst  there  existed 

*These  rails  had  endured  a  density  of  traffic  of  150,000  trains;  we  had 
not  been  able  to  find  new  rails  of  the  same  length  in  the  stock  of  the  company. 


NATURE   AND  OBJECTS   OF  EXPERIMENTS.  11 

cracks  in  the  surface  of  over  a  third  of  the  wood  cross  ties.  This 
difference  in  the  stability  of  the  gravel  evidently  arises  from  the 
pronounced  bending  of  the  wooden  ties. 

As  a  result  of  the  super-elevation  and  grade,  argillaceous  nature 
of  the  ballast  and  of  the  subsoil,  the  composite  cross  ties,  principally 
those  of  the  even-joint,  rested  on  a  muddy  bed,  and  the  water  vis- 
ibly churned  at  the  passage  of  each  train.  This  bed  was  then  es- 
sentially elastic,  and  this  elasticity  varied  with  the  quantity  of 
water.  The  cross  tie  was  not  unwedged,  as  one  would  suppose,  for 
it  always  rested  on  its  blocks,  which  were  buried  more  or  less  con- 
sidering this  condition.  The  wood  cross  ties  were  found  in  nearly 
the  same  situation,  with  this  difference,  however,  that  their  bed 
was  more  solid  by  reason  of  the  ballast  being  less  argillaceous. 

On  the  other  hand,  the  defective  profile  of  the  rails  employed, 
which  has  been  pointed  out  above,  produced  disagreeable  uneven- 
ness  in  the  stability  of  the  cross  ties  which  underwent  the  shocks. 
The  joints  were  particularly  bad  in  consequence  of  the  flattening 
of  the  ends  of  the  rails,  to  such  an  extent  that  it  was  necessary  to 
sustain  them  by  wedges  placed  between  the  splices  and  the  under 
part  of  the  rail  head;   these  defects  were  but  little  corrected.    The 
experiment  was  therefore  made   under  the   most  unfavorable   con- 
ditions, but,  nevertheless,  the  results  obtained  have  been  excellent. 
The  fastenings  have  held  without  our  having  been  obliged  to  re- 
touch them.    The  tamping  was  maintained  on  a  horizontal  bed  over 
the  whole  length  of  the  blocks,  whilst  it  has  a  tendency  to  form 
under  the  wood  cross  ties  either  a  concave  basin,  on  the  edges  of 
which  they  rest  in  a  state  of  repose,  or  a  convex  cap,  on  the  summit 
of  which  they  find  support.     The  rewedged  joints  no  longer   pre- 
sented a  sensible  unevenness  at  the  passage  of  vehicles;  the  rolling 
was  then  very  much  improved. 

Mr.  Ferry,  Sub-Engineer  of  the  company,  had  caused  a  track  to 
be  extended  in  a  cul-de-sac  of  the  Bourg  station,  along  the  loading 
quay  for  animals,  in  order  to  permit  experiments  on  the  length  of 
cross  ties  and  of  their  tamped  bed,  and  to  join  them  with  the  tests 
executed  up  to  that  day,  by  means  of  loads  perfectly  defined,  acting 
always  under  the  same  conditions. 

* 

The  subsoil,  specially  cleared  away  for  the  laying  of  the  track, 
consisted  of  an  argillaceous  conglomerate,  enclosing  small  pebbles 
of  gravel;  it  was  not  therefore  perfectly  homogeneous.  The  ballast 
was  fine  gravel.  There  were  successively  placed  in  the  track  thus 
established  composite  cross  ties,  wood  cross  ties  and  cross  ties 
wholly  metallic. 


12  TRACK  DEFORMATIONS. 

In  order  to  be  able  to  better  appreciate  the  difference  of  stabil- 
ity of  composite  and  wood  cross  ties,  and  to  eliminate  all  influences 
on  this  stability,  independently  of  their  own  resistance,  such  as 
inclination  on  the  curves,  the  elasticity  of  the  road  bed,  and  the  argil- 
laceous nature  of  the  ballast,  we  deemed  it  a  duty  to  remove  the 
cross  ties  which  were  laid,  as  we  have  pointed  out,  below  the  sta- 
tion of  Saint-Etienne-du-Bois,  and  to  put  them  above  at  the  entrance 
of  that  same  station,  on  tangent,  on  a  very  solid  road  bed,  and 
finally  to  ballast  them  with  gravel  purged  as  much  as  possible  from 
clay.  I  had,  in  advance,  the  ends  of  the  cross  ties  cut  off,  in  order 
to  leave  them  exactly  of  the  length  of  2  m  20  (7  ft.  2.64  in.),  cor- 
responding to  the  minimum  bending,  and  to  the  distance  between 
the  extremities  of  the  blocks.  The  metallic  skeleton  projected,  in 
fadt,  beyond  the  wood  by  0  m  15  (5.91  in.)  at  each  end,  and  this 
excess  of  length  was  quite  useless. 

The  wood  cross  ties  were  laid  at  each  of  the  extremities  of 
the  section  thus  selected  to  serve  for  terms  of  comparison.  They 
were  of  the  ordinary  dimensions  and  length.  All  these  cross  ties 
were  provided  with  P.  M.  rails,  absolutely  new,  whose  rolling  sur- 
face was  consequently  as  good  as  possible.  The  ends  of  the  rails 
laid  on  composite  cross  ties  were  joined  by  ordinary  splices;  on  the 
wood  cross  ties,  angle  bars  were  used. 

When  the  track  had  taken  its  bed,  the  curves  of  flexure  of  the 
cross  ties  were  determined  anew;  then  account  was  taken  of  their 
tamping  and  of  their  depression  in  the  track  after  the  passage  of 
the  same  number  of  trains.  Finally  the  study  of  the  joint,  so  inter- 
esting and  so  difficult,  was  commenced. 

These  experiments,  which  have  already  been  pursued  for  a 
year,  have  not  yet  sufficiently  advanced  for  me  to  have  made  known 
the  results.  I  can,  however,  already  affirm  that  everything  has 
happened  as  I  had  foreseen,  and  that  the  composite  cross  ties  of 
2  m  20  (7  ft.  2.64  in.)  have  a  stability  in  the  track  much  superior 
to  that  of  the  ordinary  cross  ties,  other  things  being  equal.  That 
is  due  to  their  greater  rigidity  and  to  the  tamped  bed  which  is  main- 
tained in  the  condition  in  which  it  was  placed. 

It  will  be  interesting,  after  a  longer  period  in  the  track,  to  make 
known  and  explain  the  facts  which  will  be  found. 


CHAPTER  II. 
MOVEMENTS    TO   WHICH    TRACK   IS    SUBJECTED. 

The  tracks,  made  as  has  been  explained,  have  permitted  the 
study  of  the  principal  movements  to  which  they  are  subjected,  and 
which  cause  their  deformations;  they  are  produced  in  a  longitudinal 
direction,  in  the  direction  of  the  travel  of  the  trains,  and  in  the 
transverse  direction. 

It  is  important  to  analyze  them  with  care,  in  order  to  seek  the 
means  for  remedying  them. 

LONGITUDINAL    MOVEMENT. 

The  weight  on  the  wheel  is  distributed  over  a  certain  number 
of  cross  ties,  and  imposes  on  them  a  vertical  movement,  directed  at 
first  from  low  to  high,  then  from  high  to  low,  when  the  load  is 
brought  near. 

Mr.  Coiiard  has  recorded  these  facts  by  means  of  the  apparatus 
of  Marey,  and  has  derived  from  the  experiments  which  he  performed 
in  June,  1903,  between  Melun  and  Bois-le-Roi,  the  following  conclu- 
sions: 

When  the  first  wheel  of  the  engine  is  at  6  meters  (19.68  ft.), 
the  movement  of  the  cross  tie,  .from  low  to  high,  begins. 

When  the  first  wheel  of  the  engine  is  at  3  meters  (9.84  ft.),  the 
displacement  is  maximum. 

When  the  first  wheel  of  the  engine  is  at  2  meters  (6.56  ft.),  the 
movement  from  high  to  low  below  the  initial  position  begins. 

When  the  wheel  is  on  the  cross  tie  the  depression  of  the  tie 
reaches  its  maximum. 

But  these  figures  are  only  averages,  and  the  mean  distance  of 
2  meters  (6.56  ft),  from  which  place  the  depression  of  the  cross  tie 
in  the  ballast  commences,  goes  on  increasing  from  the  advance  to 
the  following  end.  It  follows  that  the  bending  rail  in  its  first  half, 
over  shorter  length,  ought  to  curve  more  in  that  part. 

Mr.  Ast,  Director  of  Ways  and  Cross  Ties  (Austria-Hungary), 
by  the  use  of  instantaneous  photography  has  confirmed  the  results 
and  shown,  afterwards,  that  the  ballast  was  compressible  and  under- 
went movements  analogous  to  those  of  the  cross  tie,  although  less. 


14  TRACK  DEFORMATIONS. 

It  was  our  desire  to  verify  the  results  given  by  those  engineers, 
and  to  observe  the  influence  of  more  rigid  cross  ties  on  the  vertical 
movement.  We  had  at  our  disposal,  aside  from  the  wood  cross  ties 
in  use  on  the  Paris,  Lyons  &  Mediterranean  System,  the  composite 
cross  ties  laid  as  described  in  one  of  the  main  tracks  of  the  line 
from  Mouchard  to  Bourg.  The  experiment  was  made  by  an  engine 
with  three  axles  coupled  weighing  32  tonnes  (35.27  net  tons)  in 
working  order,  a  tender  of  24  tonnes  (26.46  net  tons),  and  a  car. 

This  train  was  moved  on  a  bay  provided  with  ordinary  wood 
cross  ties,  then  on  another  bay  with  composite  cross  ties,  each  of 
these  bays  being  comprised  between  two  successive  joints.  The  wood 
cross  ties  supported  P.  L.  M.-A.  rails,  the  composite  cross  ties  P.  M. 
rails,  having  a  greater  weight  and  rigidity. 

The  first  axle  of  the  engine  was  brought  as  near  as  possible 
to  the  cross  tie  to  be  tested.  There  were  marked  off,  by  a  special 
rule  and  a  gage,  of  which  a  description  will  be  given  further  along, 
when  we  study  the  flexure,  points  on  the  rail  at  each  cross  tie;  these 
same  points  were  retaken  at  each  stoppage  of  the  train,  that  is  to 
say,  each  time  it  advanced  a  length  corresponding  to  the  spacing 
of  the  cross  ties.  The  points  thus  marked  off  on  each  rail  were 
joined,  for  each  position  of  the  train,  by  a  full  line  where  it  refers 
to  the  movement  on  the  track  composed  of  ordinary  cross  ties,  and 
by  a  dotted  line  where  it  refers  to  the  track  with  composite  cross 
ties.  Each  of  these  lines,  represented  in  Figs.  4  and  5,  gives  the 
undulatory  movement  of  the  track  in  each  of  the  positions  of  the 
train,  when  the  latter  is  stopped  successively  right  at  each  of  the 
cross  ties.  This  movement  is  quite  like  that  which  has  been  de- 
scribed by  Mr.  Coiiard;  when  the  first  wheel  of  the  engine  is  found 
at  a  certain  distance  (about  6  m.)  (19.68  ft.)  from  a  cross  tie, 
the  movement  from  low  to  high  commences;  the  latter  is  maximum 
.at  3  meters  (9.84  ft.),  then  it  reverses  and  the  cross  tie  sinks,  the 
maximum  corresponding  with  the  passage  of  the  first  axle. 

The  part  of  the  track  in  which  the  composite  cross  ties  were 
placed,  was  much  worse,  as  has  been  explained  above,  than  that 
where  the  ordinary  cross  ties  were  located.  The  roadbed  was  less 
hard  and  above  all  the  ballast  was  more  moist,  more  muddy;  the 
consequence  of  this  was  that  the  composite  cross  ties  were  not 
perhaps  buried  more  at  certain  points  than  the  wood  cross  ties 
placed  under  more  favorable  conditions;  but,  as  a  whole,  the  profile 
with  composite  cross  ties  is  much  less  accentuated  than  that  with 
wood  cross  ties.  The  rise  is  much  less  marked,  that  is  to  say, 
\the  track  as  a  whole  being  more  rigid,  the  oscillatory  movement 


MOVEMENTS    TO  WHICH  TRACK    IS   SUBJECTED. 


15 


is  diminished.  The  ramps,  which  the  train  has  to  surmount,  are 
less,  that  is  to  say,  the  traction  is  better  and  exerts  a  smaller  effort. 
The  joint  which  is  induced  from  low  to  high,  by  the  oscillatory 
movement  of  the  track,  and  which  by  this  fact  is  disorganized,  as 
will  be  seen  further  along,  is  not  so  to  speak  more  affected,  when 
the  track  is  provided  with  composite  cross  ties. 
The  table  herewith  exhibits  the  results: 


Designation 

Ordinary 

of  position 

,  —  cross 

ties  — 

.first  axle  of 

lOths  of 

lOOths 

engine. 

millim. 

an  inc 

1 

16 

6 

>.> 

18 

7 

3 

26 

10 

•i 

33 

13 

5 

43 

17 

6 

34 

14 

7 

23 

9 

8 

17 

7 

9 

14 

5 

10 

11 

4 

11 

6 

2 

12 

8 

3 

13 

15 

6 

14 

16 

6 

1.5 

18 

7 

16 

23 

9 

17 

23 

9 

18 

27 

11 

19 

24 

10 

20 

14 

5 

21 

13 

5 

22 

14 

5 

23 

1 

24 

8 

3 

Asceurs  to  overcome ->, 

Composite 

< cross  ties. ^ 

lOths  of    lOOths  of 
millim.       an  inch. 


Movement  of  the 

( Joint. — : .. 

Ordinary     Composite 
cress  ties,     cross  ties. 


17 

i 

1 

0 

17 

1 

0 

4 

20 

S 

2 

4 

25 

10 

1 

"Z 

17 

7 

3 

1 

14 

5 

2 

0 

11 

4 

2 

0 

10 

4 

4 

1 

17 

7 

2 

3 

16 

6 

0 

4 

14 

5 

16 

9 

6 

2 

11 

11 

20 

8 

0 

1 

20 

8 

2 

3 

19 

8 

2 

2 

14 

5 

3 

0 

11 

4 

6 

0 

8 

3 

5 

0 

14 

5 

6 

0 

11 

4 

6 

1 

7 

3 

5 

1 

14 

3 

6 

3 

15 

6 

8 

3 

7 

3 

18 

13 

324 

106 

65 

324 

106 

65 

—  =13 

5 

=  4.4 

=-2.7 

24 

24 

24 

Total 445 

445 

Mean =18  7 

24 

NOTE. — The  positions  from  1  to  12  correspond  to  the  track  on  the  long 
radius  ;  those  from  13  to  24  to  the  track  on  the  short  radius. 

In  recapitulation,  the  use  of  rigid  cross  ties  has  diminished  the 
^effort  of  traction  in  the  proportion  13  to  18,  that  is  to  say,  tnat  the 
tractive  effort  on  rigid  ties  is  about  30  per  cent,  less  than  on  the 
ordinary  cross  ties.  The  movement  of  the  joint  is  reduced  by  about 
•one-half.  The  result  was  indeed  what  one  n.ould  expect.  It  demon- 
strates the  importance  of  the  longitudinal  movement,  and  the  ad- 
vantage of  diminishing  it  by  using  rigid  tracks. 

It  can  be  objected  that  the  comparison  made  is  not  perhaps 
entirely  exact,  since  the  P.  L.  M.-A.  track,  laid  with  ordinary  cross 
ties,  is  less  rigid  than  the  P.  M.  track  with  composite  cross  ties, 


16  TRACK  DEFORMATIONS. 

and  that  everything  in  the  case  in  hand  was  combined  to  obtain 
a  more  favorable  result.  That  objection  ought  to  be  dismissed,  for 
the  influence  of  the  subsoil  and  of  the  ballast  counterbalanced,  and 
more,  tne  rigidity  of  the  rail. 

TRANSVERSE    MOVEMENT. 

The  transverse  movement  of  the  track  is  of  still  greater  im- 
portance than  the  longitudinal  movement,  and  produces  more  im- 
portant effects.  It  arises  from  this  that  the  cross  tie  is  not  only 
buried  in  the  ballast,  but  it  bends;  each  of  its  points  seems  then 
to  be  buried  in  the  ballast  by  unequal  quantities,  and  this  unequal 
sinking  results  in  the  greatest  deformations  of  the  track. 

Mr.  Couard  has  studied  the  question  with  all  desirable  care/ 
but  his  measuring  instruments,  doubtless  imperfect,  have  not  per- 
mitted him  to  draw  from  his  study  all  the  conclusions  which  should 
nave  been  derived.  The  form  of  the  curve  of  deformation  which 
he  has  found  (Revue  des  Chemins  de  Fer,  July,  1897,)  is  such  that 
it  does  not  permit  the  deduction  of  a  general  law  from  the  phenom- 
ena observed.  However,  that  engineer  has  found  that  the  vertioa7 
displacements  of  cross  ties  hardly  reach  3  millimeters  (%  in.), 
and  that  they  are  not  proportional  to  the  weights  supported.  He 
has  concluded  from  it  "that  the  cross  ties  fixed  to  the  rail  remain, 
at  certain  points,  suspended  above  the  ballast,  and  that  right  at 
the  rail  there  is  formed,  under  even  the  best  tamped  cross  ties, 
some  depressions  of  ballast  on  the  edges  of  which  the  cross  tie 
is  supported;  that  under  the  passage  of  a  wheel  even  lightly  loaded, 
the  cross  ties  come  in  contact  with  the  ballast  and  deflect  to  the 
depth  of  the  depressions;  that  from  this  moment  only  the  im- 
portance of  the  bending  is  proportional  to  the  load."  Basing  their 
study  on  the  theoretical  researches  of  Winckler,  some  notable  engi- 
neers, Shwedler,  Hoffmann,  Lehwald,  Riese  and  Zimmermann,  have 
studied  the  manner  in  which  cross  ties  behave  when  resting  on 
an  elastic  foundation.  They  have  determined  the  deformations 
which  they  experienced  under  the  effect  of  a  load  in  repose,  and 
estimated  the  magnitude  of  the  tensions  of  flexure  which  result 
from  it. 

If  the  cross  ties  were  completely  rigid  there  would  result  a  uni- 
form distribution  of  the  pressure  on  the  ballast.  But  it  is  not  so; 
the  cross  tie  is  unequally  buried  in  the  ballast,  in  such  a  way  that 
the  pressure  is  no  longer  uniform,  but  is  greater  right  at  the  rails. 

The  cross  tie  should,  then,  be  considered^  as  a  continuous  beam 
resting  on  an  elastic  base  unsolved  for  continuity,  and  supporting 


MOVEMENTS   TO   WHICH    TRACK    IS    SUBJECTED.  17 

a  vertical  load  at  two  points.  The  German  engineers  designate  by 
load,  on  rail  the  pressure  which  the  rail  exercises  on  the  cross  tie, 
and  that  pressure  depends  as  much  on  the  transverse  section  of 
the  rail  as  on  that  of  the  cross  ties,  as  well  as  on  their  spacing 
and  on  their  bedding.  They  admit,  also,  that  the  deformations  ana 
the  strains  experienced  by  the  cross  tie  vary  with  the  length  and 
nature  of  the  tamped  bed. 

Starting  from  these  premises,  they  have  found  that  the  elastic 
curve  of  a  cross  tie  was  represented  by  Figure  1  or  by  Figure  2, 


Fig.    1.  Fig.  2. 

according  as  the  cross  tie  was  2  m  40  (7  ft.  10.4  in.)  or  2  m  70 
(8  ft.  10.3  in.)  long. 

The  cross  tie  of  2  m  40  (7  ft.  10.4  in.)  would  be  deformed 
then  according  to  a  convex  curve;  the  maximum  of  the  sinking 
would  be  produced  at  the  extremities  and  would  continue  dimin- 
ishing toward  the  middle.  But,  with  a  cross  tie  2  m  70  (8  ft. 
10.3  in.)  long,  the  maximum  sinking  would  be  produced  nearly 
under  the  rail,  and  the  permanent  compression  of  the  ballast  would 
be  diminished  from  this  point  nearly  uniformly  on  both  sides,  in 
such  a  way  that  even  a  deeper  sinking  would  not  have  as  a  con- 
sequence a  change  in  the  inclination  of  the  rails,  nor  in  the  spread- 
ing of  the  track. 

The  theory  assumes  an  absolutely  homogeneous  cross  tie  with 
a  tamped  bed  continuous  and  uniform  over  its  entire  length.  The 
German  engineers  think  indeed  that  this  hypothesis  is  not  realized 
in  practice;  they  recognize  also  that  short  cross  ties  present  in 
reality  a,  curve  of  deformation  similar  to  that  of  long  cross  ties; 
imt  they  explain  this  difference  between  theory  and  practice  by  the 
stronger  tamping  of  the  heads  of  the  cross  ties. 

The  incomplete  results  given  by  Mr.  Coiiard,  the  very  ingenious 
theory  of  the  German  engineers,  rendered  necessary  the  study  of 
the  deformation  of  a  cross  tie  under  a  load,  of  the  manner  in 
which  the  ballast  behaves  under  the  cross  tie,  of  its  more  or  less 
extent  of  compressibility,  of  its  more  or  less  extent  of  elasticity. 
The  experiments  which  have  been  carried  on  during  nearly  two 
years  have  had  this  object  as  their  principal  end. 


CO 
D) 


MOVEMENTS    TO   WHICH   TRACK   IS   SUBJECTED.  19 

CURVES    OF    DEFORMATION    OF    CROSS    TIES. 

They  have  taken  place  under  the  most  different  conditions  of 
temperature  and  humidity,  in  such  a  way  as  to  have  the  terms  of 
comparison  numerous,  to  be  able  to  compare  them  and  to  deter- 
mine an  aggregation  of  facts  which  may  not  be  controvertible. 
They  have  been  carried  on  at  three  different  periods;  from  the 
4th  to  the  15th  of  May,  during  a  rainy  period,  after  a  prolonged 
season  of  rain ;  from  the  19th  ,to  the  30th  of  June,  after  a  drier 
season,  and  finally  at  the  end  of  the  month  of  July,  1903,  at  a 
time  when  the  rains  had  just  returned.  (I  do  not  give  an  account 
of  the  last  experiments,  which  only  confirm  the  results  of  those 
which  are  given.)  In  all  the  tests  the  ballast,  composed  as  has 
been  pointed  out  above  of  rough  gravel  agglomerated  with  argilla- 
ceous sand,  was  particularly  moist,  and  consequently  muddy.  This 
state  of  moisture  was  so  great  that  it  was  maintained  even  in  the 
period  of  heat  in  the  months  of  June  and  July.  The  drying  of 
the  ballast  was  not  completed,  by  reason  of  the  position  on  a 
curve,  and  of  the  inclination  toward  the  interior  of  the  track,  which 
is  the  consequence  of  it  (0  m  083)  (39/32  in.),  the  loads  were  car- 
ried on  the  rail  on  the  side  of  the  short  radius.  The  ballast  was 
therefore  more  compressed  on  that  side  than  on  the  other;  its  per- 
manent sinking  was  consequently  more  pronounced,  and  it  pre- 
served, after  the  passage  of  vehicles,  the  form  of  a  plane  slightly 
inclined  toward  the  center  of  the  curve.  The  cross  tie  rested  thus 
toward  the  extremity  of  the  inclined  plane  on  the  side  of  the  long 
radius;  the  water  accumulated  in  the  lowest  part  of  this  inclined 
plane,  that  is  to  say  on  the  side  of  the  short  radius.  The  ballast 
was  therefore  particularly  wet  on  that  side;  it  was  possible,  by 
making  a  trench  right  at  the  cross  ties,  to  let  the  water  flow  off, 
which  rendered  the  support  very  elastic.  The  drop  of  the  vehicles 
from  the  advance-rail  to  the  following-rail  rendered  this  effect  still 
more  sensible  right  at  the  cross  ties  of  the  following  end  of  the 
even-joint;  the  hammering  of  the  ballast  by  the  shocks  of  the  wheels 
augmented  the  depression  between  the  bottom  of  the  cross  tie  and 
the  upper  part  of  the  support,  a  depression  in  which  the  water  accu- 
mulated. Also,  at  the  passage  of  vehicles,  the  water  was  projected 
vertically;  the  cross  tie  and  the  rail  bore  traces  of  these  ejections. 
This  fact  was  not  isolated  and  peculiar  to  the  part  of  the  track 
which  we  studied.  Wherever  the  ballast  is  but  little  permeable, 
and  can  form  a  cake  more  or  less  firm,  the  same  phenomenon  is 
observed,  which  shows  above  all  right  at  the  cross  ties  of  the  even- 


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24  TRACK  DEFORMATIONS. 

joint  (of  whatever  nature  they  may  be)  by  the  projection  of  mud 
on  the  rail.  The  hammering  of  the  ballast  produces  a  void  under 
the  point  of  application  of  the  load;  this  void  is  filled  little  by  little 
with  the  materials  of  the  roadway,  which  are  slowly  displaced, 
falling  into  the  inter-track  space  or  on  the  outside  space,  and  flow- 
ing between  the  two  rails.  The  ballast  is  as  though  screened  by 
the  vibration  of  the  cross  tie  of  the  following  end  of  the  even-joint; 
the  finest  materials  pass  under  the  rail  and  cause  the  coarser 
materials  to  ascend  in  the  inter-rail  space.  In  this  part  of  the 
track  it  is  also  remarked  that  the  screw  spikes  of  the  cross  tie  of 
the  following  end  of  the  even-joint  are  subjected  to  a  wrenching, 
because  they  support  at  their  lower  extremity  a  hydraulic  pressure 
which  expels  them  from  their  holes,  and  that  the  more  rapidly 
as  the  insufficiently  creosoted  wood  is  submitted  to  the  alternations 
of  dryness  and  wetness  and  deteriorates  in  consequence  of  the  oxida- 
tion of  the  screw  spike.  In  order  to  have  a  good  track  it  is  very 
important  to  select  a  gravelly  ballast  purged  from  earth  and  above 
all  from  clay. 

The  experiments  thus  executed  in  a  mediocre  ballast,  resting  on 
a  compressible  bed,  have  then  taken  place  under  unfavorable  con- 
ditions, the  results  obtained,  and  the  information  which  will  be 
derived  from  them  will  have  a  bearing  which  we  should  not  slight. 

The  most  numerous  experiments  have  been  carried  on  in  a 
static  state,  because  it  resulted  from  similar  tests  made  by  Mr.  Ferry. 
Sub-Engineer,  at  Bourg,  that  the  flexures  in  the  dynamic  state  are 
not  superior  to  those  which  are  realized  in  a  static  state.  The 
curve  of  deformation  of  cross  ties  can  be  modified  in  its  general 
form,  but  its  parts  preserve  the  same  relation  between  themselves, 
maintaining  the  same  flexure  as  in  the  static  state.  This  fact  has 
been  verified  on  the  wood  cross  ties  provided  with  P.  L.  M.-A.  rails. 

The  determination  of  the  curves  of  deformation  of  cross  ties 
has  been  made  with  extreme  care,  taking  all  desirable  precautions. 

MEASURING    APPARATUS    FOR    EXPERIMENTS    IX    THE    STATIC    STATE. 

There  were  first  placed  in  the  surface  of  the  wood  cross  ties 
screws  with  square  heads  distributed  over  their  whole  length  and 
giving  15  or  16  fixed  points,  which  were  to  serve  as  bench  marks 
for  the  determination  of  the  deformation.  A  rigid  steel  rule  in 
the  form  of  a  T  (Fig.  6)  presented,  right  at  the  points,  whose 
spacing  was  the  same  for  all  cross  ties,  vertical  rods  terminated 
by  a  notch,  in  which  was  brought,  while  resting  on  the  screw  with 
square  head,  a  gage  in  the  form  of  an  inclined  plane,  whose  divi- 


UNIVERSITY  j 

^AUFO^fe^ 
MOVEMENTS   TO   WHICH  TRACK   IS    SUBJECTED.  25 

sions  were  calculated  in  a  manner  to  correspond  with  a  tenth  of 
a  millimeter.  The  inclination  of  the  inclined  plane  had  been  so 
chosen  that  the  interval  between  two  divisions  was  at  least  of 
2  centimeters  f'Yioo  in.),  which  allowed  estimating  the  tenth  of 
a  millimeter  with  exactness.  The  rule  was  fixed  in  an  unchange- 
able manner  to  two  stakes  of  strong  dimensions,  buried  in  the  em- 
bankment about  1  m  10  (3.61  ft.),  in  order  to  eliminate  the  influ- 
ence of  the  load  on  the  supports  of  the  rule.  When  the  rule  was 
in  place,  an  observer  introduced  the  wedge-shaped  gage  in  the 
notch,  while  maintaining  it  horizontally  on  the  head  of  the  screw, 
and  stopped  it  at  the  moment  when  it  commenced  to  become  wedged; 
he  then  made  a  first  reading  on  all  the  points  of  reference,  pro- 
ceeding, for  example,  from  left  to  right,  then  a  second,  proceed- 
ing in  the  reverse  direction,  from  right  to  left.  The  readings  made 
were  recorded  by  the  employees  of  the  Board  of  Control  and  those 
of  the  P.  'L.  M.  Co.,  and  the  mean  of  them  was  taken,  which  thus 
gave  the  actual  position  of  the  cross  tie. 

The  vehicle,  which  served  to  load  the  cross  tie  considered, 
was  brought  up,  always  taking  care  to  place  the  same  wheels  at  the 
same  spot,  with  reference  to  the  piece  submitted  to  the  test;  it 
was  allowed  to  remain  during  about  10  minutes,  and  the  readings 
were  recommenced,  which  caused  some  difficulties,  since  the  head 
observer  was  obliged  to  pass  under  the  frame  of  the  engine  and  to 
operate  stretched  out  to  his  full  length.  In  like  manner  two  suc- 
cessive readings  were  made,  and  the  mean  of  them  was  taken,  as 
has  been  recited  above;  the  difference  between  the  inscribed  means 
gave  the  deformation  of  a  cross  tie  under  the  load  considered.  It 
was  necessary  to  count  on  an  Tiour  at  least  for  the  aggregate  of 
the  readings,  and  the  necessary  delays  during  the  passage  of  trains 
made  the  operation  require  a  very  long  time. 

The  preparation  of  the  working  place  and  the  establishment 
of  the  measuring  apparatus  has  been  made  by  Mr.  Ferry,  Sub-Engi- 
neer of  the  P.  L.  M.  Co.,  who  has  carried  on  experiments  of  this 
kind  for  more  than  20  years,  and  who  allies  with  a  consummate 
experience  a  sagacity  truly  remarkable. 

MEASURING   APPARATUS    FOR*  THE    EXPERIMENTS    IN    THE    DYNAMIC    STATE. 

Mr.  Ferry  employed  for  the  experiments  in  a  dynamic  state 
a  measuring  apparatus  which  had  previously  served  for  studying 
the  deformation  of  cross  ties  in  a  static  state  as  well  as  In  a  dyna- 
mic state.  It  is  extremely  simple  and  strong;  it  presents  then 
from  this  point  of  view  an  incontestable  superiority  over  the  appar- 


CO 
D) 


MOVEMENTS    TO  WHICH  TRACK    IS   SUBJECTED. 


27 


atus  employed  for  the  same  object,  which  would  give  perhaps  more 
precise  results,  but  whose  indications  require  corrections  always  dif- 
ficult to  make,  by  reason  of  the  greater  delicateness  of  the  measure- 
ments (apparatus  of  Marey).  If  these  corrections  are  incomplete, 
the  indications  given  conduce  to  results  which  cannot  be  utilized. 
The  measuring  apparatus  (see  Fig.  7)  was  essentially  com- 
posed of  a  stylus  arranged  in  a  stable  manner  at  the  face  of 
a  plate  of  smoked  glass  and  fixed  on  the  points  o>f  the  cross  tie 
under  observation.  The  black  smoke  deposited  on  the  glass  plate, 


Fig.  A '-  Section  of  a  Cross  Tie  pror/cfecf 
wifh  a  reference  mark. 


-  Fbs/f/on  of  &  reference  marks  /? 
the  length  of  a  Cross  Tie,  /'n  p/art. 

Fig.  7 — Flexure  of  Ties  Under  Load,  Shown  by  Reference  Marks. 

which  was  displaced  at  the  same  time  and  by  the  same  amount 
as  the  points,  was  removed  by  the  point  of  the  stylus;  the  height 
of  the  part  removed  gave  the  value  of  the  deflection,  or  of  the  rais- 
ing of  a  cross  tie  at  the  points  considered.  The  reading  of  this 
height  was  made  by  means  of  a  magnifying  glass  nearly  to  the  tenth 
of  a  millimeter. 

The  stylus,  with  flat  point  of  tempered  steel,  was  mounted  on 
a  very  flexible  spring,  which  could   be  approached   to  or  removed 


MOVEMENTS    TO   WHICH   TRACK   IS   SUBJECTED.  29 

from  the  glass  plate  at  will,  with  the  aid  of  a  thumb  screw.  The 
glass  plate  was  fixed  by  screws  on  one  of  the  faces  of  a  cross  tie, 
then  smoked  in  the  flame,  of  a  candle  at  the  moment  when  it  was 
desired  to  put  it  in  service.  The  thumb  screw  passed  through  an 
iron  rod  and  simply  rested  on  the  spring  which,  left  free,  moved 
back  and  forth  on  the  rod  fixed  by  means  of  two  bolts  on  a  stake 
deeply  buried  in  the  soil. 

In  order  to  make  an  observation,  the  screw  is  pressed  against 
the  spring  until  the  point  of  the  stylus  comes  in  contact  with  the 
blackened  plate.  In  this  position  a  light  blow  is  given  to  it,  which 
makes  it  oscillate  and  defines  a  horizontal  trace  of  2  or  3  milli- 
meters (Vioo  to  12/100  in.)  length  on  the  black  smoke,  a  trace  which 
forms  the  reference  mark. 

At  this  moment  one  can  either  place  the  vehicle  on  the  cross 
tie,  or  allow  trains  at  speed  to  pass  over  it.  The  height  of  the 
part  of  the  glass  plate  rubbed  off  by  the  point  of  the  stylus  gives, 
above  the  reference  mark,  the  values  of  the  depression,  and  below, 
the  uplift,  of  the  cross  tie.  The  latter  is  always  inferior  to  the 
former;  for  the  flexure  is  important  in  comparison  with  the  move- 
ment of  uplift  of  this  piece  under  the  influence  of  loads  at  a  dis- 
tance. The  successive  influence  of  each  of  the  axles  cannot  be  noted, 
but  it  is  solely  a  maximum  indication  which  is  produced. 

Mr.  Ferry,  before  providing  himself  with  the  rule  which  we 
have  described  above  for  the  study  of  the  deformations  in  a  static 
state,  employed  the  registering  apparatus  just  above,  and  determined 
with  exactness  the  form  of  that  deformation  by  placing  five  of  these 
apparatus  on  different  points  of  the  cross  tie.  He  was  then  able, 
by  comparing  the  results  obtained  with  the  rule  and  the  wedge 
on  the  one  hand,  and  the  stylus  on  the  other,  to  appreciate  the  pre- 
cision of  measurements  given  by  one  or  the  other  of  these  apparatus. 

STOCK    FOR    EXPERIMENT. 

The  first  experiments  were  made  by  an  engine  with  three  axles 
coupled,  weighing  38.58  net  tons  in  working  order,  with  tender  of 
26.46  net  tons. 

These  weights  were  thus  distributed  among  the  axles: 

Spacing.      Diam.  of  wheels 

Engine,  1st  axle 12.26  net  tons  )  6  ft.  5Vie  in.         4  ft.  3»/ia  in. 

2d       "   13.37       "         > 

3d  ..  13.37  "  4  ft.  7%  in.  4  ft.  38/ie  in. 

Tender  1st  axle''.'.'.'.'.'.'..  13.34  "  3ft.ll%ln. 

Tender  2d  axle 14.11  "  Bit.  11%  In. 


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MOVEMENTS   TO   WHICH    TRACK   IS    SUBJECTED.  33 

The  locomotive  and  its  tender  were  followed  by  a  car.  After 
having  referenced  the  top  of  the  tie  by  means  of  a  measuring  rule, 
the  train  was  brought  to  position,  in  such  a  way  that  the  third  axle 
should  be  as  near  as  possible  to  the  cross  tie.  After  leaving  it  in 
this  position  for  about  10  minutes,  the  measuring  rule  was  intro- 
duced right  at  the  cross  tie  and  the  second  reading  was  made.  (See 
Fig.  8.) 

EXPERIMENTS    OF    THE    MONTH    OF    MAY,    1903. 

The  trials  took  place  on  nine  wood  cross  ties  and  on  21  com- 
posite cross  ties;  the  curves  of  deformation  which  have  been  ob- 
served are  represented  with  a  black  line  on  Figs.  9  and  10.  The 
figures  are  inscribed  in  tenths  of  millimeters. 

It  is  remarked  that  all  the  curves  of  the  wood  cross  ties  present 
a  well  defined  figure,  always  similar,  in  the  form  of  a  basin.  The 
edges  are  slightly  inclined  up  to  a  point  near  the  rail,  nearly  at 
23.62  in.  from  the  axis  of  the  track,  and  the  bottom,  which 
unites  the  two  edges,  is  nearly  horizontal,  tending  to  rise  towards 
the  center  and  thus  presenting  its  convexity  upward.  The  maxi- 
mum sinking  of  the  cross  tie  is  produced  a  little  beyond  the  rail, 
proceeding  from  the  extremities  towards  the  center,  and  the  bend- 
ing, which  consequently  gives  unequal  distribution  of  the  pressure 
on  the  ballast,  is,  so  to  speak,  maximum  near  the  rail,  producing 
a  greater  sinking  than  at  any  other  point. 

The  trials  took  place  on  four  wood  cross  ties  provided  with 
P.  L.  M.-A.  rails,  and  five  others  provided  with  P.  M.  rails,  these 
rails  being  more  rigid  than  the  first.  Fig.  11,  No.  1,  on  which 
has  been  placed  the  mean  of  the  figures  inscribed  on  Nos.  1 
2,  3  and  4  of  Fig.  9  (full  black  line)  gives  the  general  form 
of  the  deformation  for  the  five  cross  ties  considered,  the  errors  of 
reading  being  thus  more  or  less  compensated.  This  general  form 
is  that  pointed  out  above,  a  basin  with  slight  swelling  in  the 
center.  The  mean  cross  tie  seems  to  be  depressed  only  slightly  at 
first,  a  maximum  .022  in.,  then  to  be  inflected  in  the  ballast 
proportionately  to  the  pressure  which  it  transmits  to  it.  Apart 
from  the  general  sinking,  the  piece  has  bends  in  relation  to  the 
line  which  joins  the  extremities  of  the  elastic  line  defined,  bends 
which  are  at  5.12  in.  from  the  rail  on  the  side  of  the  long  radius, 
where  the  inclined  part  comes  to  rejoin  the  bottom  of  the  basin, 
0.093  in.,  at  the  center  0.085  in.,  at  5.12  in.  from  the  rail,  on  the 
side  of  the  short  radius,  where  the  inclined  part  of  the  elastic  line 
rejoins  the  bottom  of  the  basin  0.101  in. 


34  TRACK  DEFORMATIONS. 

The  four  cross  ties  supporting  P.  M.  rails  furnish  a  mean  curve 
of  deformation  similar  to  the  first,  Fig.  11,  -  No.  2;  but  the 
mean  bending  and  sinking  which  results  from  it  are  inferior 
to  those  stated  above,  because  the  rail  is  more  rigid  and  because 
it  transmits  the  load  over  a  greater  number  of  cross  ties.  The 
deformation  reaches  the  following  values  at  the  same  points: 

5.12  in.  from  the  rail  on  the  side  of  the  long  radius .   .043  in. 

At  the  center 051   " 

5.12  in.  from  the  rail  on  the  side  of  the  short  radius 059  " 

More  rigid  rails,  distributing  the  pressure  on  a  greater  number 
of  cross  ties,  diminish  the  flexure,  and  seem  to  distribute  the  load 
in  a  more  uniform  manner  on  the  ballast. 

Tests  were  also  made  on  21  composite  cross  ties;  their  curve 
of  deformation  is  given  in  Nos.  1,  2  and  4  to  22  of  Fig.  9  (full 
black  line).  The  latter  presents  a  very  characteristic  form,  a 
horizontal  straight  line  when  the  bed  of  the  cross  tie  is  equally 
resistant,  and  one  which  inflects  on  the  side  where  it  is  the  most 
compressible.  Thus  the  cross  ties  of  the  even-joint,  those  of  the 
following  end  above  all,  which  are  submitted  to  the  shocks  in  con- 
sequence of  the  drop  of  vehicles  from  the  advance  one  to  the  fol- 
lowing one,  inflect  on  the  side  of  the  short  radius,  following  an 
inclined  plane,  whose  declivity  is  on  the  side  of  the  center  of  curva- 
ture. The  curve  of  mean  deformation,  which  includes  the  aggre- 
gate of  the  curves  obtained  (Fig.  11,  No.  2)  has  been  recorded 
on  the  curve  of  deformation  of  the  wood  cross  ties  supporting 
P.  M.  rails  like  the  composite  cross  ties,  in  order  to  show  a  com- 
parison; but  naturally  we  have  separated  from  the  mean  the  curves 
of  the  cross  ties  of  the  even-joint,  since  they  have  nothing  com- 
parable with  the  wood  cross  ties.  This  mean  curve  is  very  close 
to  a  straight  line,  since  the  maximum  flexure  is  0.012  in.  at  5.12  in. 
from  the  rail  on  the  side  of  the  short  radius;  that  is  to  say,  four 
times  less  in  value  than  with  wood  cross  ties.  The  mean  sinking 
is  about  .063  in.  less  over  its  whole  length,  except  at  its  extremity 
on  the  side  of  the  short  radius,  than  the  sinking  of  the  wood 
cross  tie. 

EXPERIMENTS    IN    JUNE,    1903. 

These  experiments  took  place  after  a  relatively  dry  period;  the 
ballast   was   somewhat   dried    up.     The   same   train    was    employed. 
The  work  was  carried  on  in  the  same  manner,  that  is  to  say  the 
third  axle  was  brought  as  closely  as  possible  to  the  cross  tie  to  be " 
studied.     The  trials  were  made  on  the  same  cross  ties  as  before; 


MOVEMENTS    TO  WHICH   TRACK  IS    SUBJECTED.  35 

they  were  extended,  however,  to  the  wood  cross  tie  21  supporting 
P.  M.  rails,  and  to  composite  cross  tie  No.  8.  The  results  of  these 
trials  are  recorded  in  Nos.  1  to  9  of  Fig.  9,  so  far  as  the  wood  cross 
ties  are  concerned,  and  in  Fig.  10  tor  the  composite  cross  ties;  they 
are  represented  by  full  line  followed  by  two  dots. 

It  will  be  seen  that  this  experiment  worked  better;  the  de- 
formation has  diminished,  which  is  natural,  since  the  ballast  was 
dried  out  and  the  cross  ties  rest  on  a  more  solid  and  more  homo- 
geneous bed  throughout  its  length.  Between  times,  besides,  the 
joints  were  rewedged  by  placing  hoop-iron  between  the  splicing  and 
the  bottom  of  the  base;  the  effect  is  perceptible,  together  with  the 
greater  solidity  of  the  bed  on  the  side  of  the  short  radius.  The 
flexure  and  the  sinking  have  diminished  considerably. 

The  mean  curve  of  deformation  of  the  wood  cross  ties  provided 
with  P.  L.  M.-A.  rails,  obtained  as  has  been  described  above 
(Fig.  11,  No.  3)  is  similar  to  that  which  was  obtained  in  the  month 
of  May  preceding,  the  same  form  of  basin  with  a  tendency  to  relief 
in  the  central  part.  The  characteristic  figures  of  this  curve  are 
the  following: 

Bending  at  5.12  in.  from  the  rail  on  the  side  of  the  long  radius.  . .  .       .092  in. 

At  the  center 091  " 

At  5.12  in.  from  the  rail  on  the  side  of  the  short  radius Ill   " 

The  apparent  sinking  of  the  cross  tie  has  sensibly  diminished; 
its  bending  has  remained  nearly  the  same,  which  should  be  ex- 
pected. For  when  the  ballast  is  impregnated  with  water  as  in  the 
first  case,  the  water  sustains  the  cross  tie  above  the  ballast.  This 
water  has  to  be  driven  out  by  the  tie,  spreading  on  both  sides.  The 
void  is  thus  more  considerable  than  when  the  ballast  is  more 
dry,  and,  in  the  last  case,  the  cross  tie,  which  is  depressed  in  pro- 
portion to  the  dryness  of  its  support,  reaches  it  more  rapidly.  In 
a  word,  this  ballast  acts  as  a  sponge  when  it  is  impregnated  with 
water;  it  swells  and  heaves  up  the  track;  on  the  contrary,  when 
it  is  dry  it  diminishes  in  volume  and  lowers  the  track. 

The  mean  curve  of  deformation  of  the  wood  cross  ties  sup- 
porting P.  M.  rails  (Fig.  11,  No.  4)  presents  the  same  minute  details, 
perhaps  less  accentuated.  The  characteristic  figures  are  the  fol- 
lowing: 

Bending  at  5.12  in.  from  the  rail  on  the  side  of  the  long  radius 043  in. 

At  the  center   043  " 

At  5.12  in.  from  the  rail  on  the  side  of  the  short  radius 055  " 

The  mean  curve  of  deformation  of  the  composite  cross  ties  is 
still  more  regular  than  in  the  first  case  (Fig.  11,  No.  4); 
the  curvature  has  diminished  a  little,  and  a  straight  line  is  almost 


36  TRACK  DEFORMATIONS. 

obtained,  since  the  bending  is  only  .008  in.,  that  is  to  say,  five 
times  less  than  that  of  the  wood  cross  ties.  The  mean  sinking  is 
no  more  than  .054  in.,  a  little  less  than  the  value  attained  in  the 
month  of  May. 

EXPERIMENTS    DURING    JULY. 

These  experiments  were  made  during  a  period  of  rain,  follow- 
ing one  of  considerable  heat.  About  the  same  conditions  were  found 
as  in  the  month  of  June.  The  ballast  was  not  more  dried  out.  The 
same  experimental  train  was  employed  and  the  third  axle  was 
placed  as  near  as  possible  to  the  cross  tie.  The  experiments  were 
made  with  the  same  cross  ties.  The  curves  of  deformation,  repre- 
sented on  Figs.  9  and  10,  present  the  same  general  form.  The  flexure 
and  the  sinking  observed  in  the  month  of  June  are  maintained,  with 
a  slight  tendency  to  diminish. 

The  mean  curve  of  deformation  of  wood  cross  ties  provided 
with  P.  L.  M.-A.  rail,  obtained  as  above  (Fig.  11,  No.  5), 
presents  some  irregularities  besides,  of  little  importance.  Thus  the 
maximum  sinking  on  the  side  of  the  long  radius  should  be  pro- 
duced at  9x/4  in.  from  the  rail;  the  central  part  should  be  nearly 
horizontal,  but  the  maximum  sinking  should  be  maintained  at 
5.12  in.  from  the  rail  on  the  side  of  the  short  radius,  and  should 
have  attained  .125  in. 

The  characteristics  of  flexure  are  the  following: 

Bending  at  5.12  in.  from  the  rail  (side  of  long  radius) 083  in. 

At  the  center 087  " 

At  5.12  in.  from  the  rail  (side  of  short  radius) 094  " 

The  general  sinking  is  a  little  more  than  in  June. 

The  curve  of  deformation  of  the  cross  ties  provided  with  P.  M. 
rails  (Fig.  11,  No.  6)  is  almost  precisely  the  same  as  that  in  June. 
The  general  sinking  of  the  ties  is  about  .051  in.  and  their  flexure 
can  be  thus  denned: 

At  5.12  in.  from  the  rail  (side  of  long  radius) 043  in. 

A  t   the  center    043  " 

At  5.12  in.  from  the  rail    (side  of  short  radius) 051   " 

The.  composite  cross  ties  are  deformed  as  a  whole,  following 
almost  a  right  line  inclined  according  to  the  superelevation.  Their 
general  sinking  is  about  .055  in.  and  the  greatest  flexure  about 
.011  in.,  four  times  less  than  that  of  the  wood  cross  ties  under  the 
same  conditions. 


MOVEMENTS    TO  WHICH   TRACK    IS    SUBJECTED.  37 

SUMMARY  AND    CONCLUSION. 

The  experiments  which  we  have  just  related  can  be  summarized 
in  the  following  table: 

(Figures  in  fractions  of  an  inch.) 

f Mean  sinking N       , Mean  flexure > 

Type  of  tie  used.                      May.      June.     July.  May.     June.      July. 

Wood,  with  P.  L.  M.  =  A  rails.  .  .    .077       .076       .084  .090       .097       .087 

Wood,  with  P.  M.  rails 066       .060       .066  .047       .043       .043 

Composite,  with  P.  M.  rails 053       .059       .059  .008       .008       .008 

The  table  shows: 

(a)  That  the  mean  sinking  of  the  wood  cross  tie  provided  with 
P.  M.  rails  is  nearly  the  same  as  that  of  the  composite  cross  tie, 
although  slightly  superior. 

(b)  That  its  flexure  is  nearly  six  times  greater. 

But  it  is  not  necessary  to  depend  upon  these  results;  if  it  is 
interesting  to  know  the  mean  sinking  and  the  flexure  of  cross  ties, 
it  is  still  more  so  to  know  the  value  of  that  sinking  and  of  that 
flexure  right  at  the  rail.  It  is  given  in  the  table  below: 

Sinking  and  flexure  right  at  rail. 

, Month  of % 

Type  of  tie.  May.  June.          July.        Mean  flexure. 

Wood  with  P.M.  rails 087  in.       .083  in.       .081  in.  .084  in. 

Composite  with  P.M.  rails 073  "         .046  "        .062  "  .065  " 

Thus  the  movement  of  a  track  is  reduced  by  25  per  cent,  by 
the  employment  of  the  composite  cross  tie;  and  this  reduction  would 
be  still  more  considerable  with  rails  less  worn  and  a  ballast  less 
spongy.  Another  interesting  fact  brought  out  by  these  experiments 
is  that  the  wood  tie,  which  is  regarded  as  bearing  over  its  whole 
length,  descends  in  the  track  by  a  greater  quantity  than  the  com- 
posite tie,  which  has  only  a  limited  bed,  4.59  ft. 

We  have  sought  the  cause  of  this  anomaly,  which  did  not,  at 
first  view,  appear  explicable.  The  composite  tie  exercises  a  uniform 
pressure  on  the  ballast  at  each  of  its  extremities  over  a  length 
of  27.56  in.;  the  cube  of  ballast  elastically  displaced  by  this  pres- 
sure is  proportional  to  the  hatched  surface  of  Fig.  11,  No.  6. 
(Experiments  of  July,  1903).  On  the  side  of  the  short  radius 
this  surface  is  .01942  sq.  in.,  and,  on  the  side  of  the  long  radius,  is 
.01307  sq.  in.;  these  two  numbers,  1,942  and  1,307,  are  respectively 
proportional  to  the  cube  of  the  ballast  displaced.  Now  this  cube 
is  itself  proportional  to  the  pressure  received  by  the  ballast  within 
the  limits  of  elasticity,  which  ought  not  to  be  reached  in  the  par- 
ticular case;  it  follows,  then,  that  the  wood  cross  tie,  which  exer- 
cises on  its  own  account  an  equal  pressure,  being  submitted  to 
the  same  loading,  ought  to  displace  a  volume  of  ballast  equal  to 


38  TRACK  DEFORMATIONS. 

that  which  is  compressed  by  the  blocks  of  the  composite  cross  tie, 
and  that  its  real  length  of  support  is  determined  by  this  condition. 
Thus,  in  the  particular  case,  the  length  of  support  of  the  wood 
cross  tie  ought  to  be  the  height  of  the  mixti-lineal  trapezium  com- 
prised between  the  original  axis  of  the  cross  tie  and  its  curve  of 
deformation,  the  surface  of  which  trapezium  should  be  equal  to 
that  of  the  hatched  part.  It  is  thus  found,  by  neglecting  the  ex- 
tremities of  the  cross  tie  which,  being  removed  from  the  center 
of  pressure,  should  react  feebly,  that  the  surface  of  support  of  the 
wood  cross  tie,  which  is  indeterminate  by  reason  of  the  irregularity 
of  the  tamping,  does  not  exceed  the  length  of  the  blocks  of  the 
composite  cross  tie,  that  is  to  say  that  it  extends  about  13.78  in. 
on  both  sides  of  the  axis  of  the  rail.  The  central  part  of  the  cross 
tie  is,  therefore,  not  utilized  to  distribute  the  pressure,  and  serves 
only  as  a  tie  bar  to  unite  the  support  of  the  rail.  It  is  even 
probable  that  this  central  bed  not  only  does  not  press  on  the  bal- 
last, but  even  that  it  is  uplifted  by  a  kind  of  sub-pressure,  due  to 
the  elastic  compression  of  the  ballast  right  at  the  points  of  sup- 
port. The  ballast  can  be  likened  to  an  elastic  matter,  peat  for 
example,  which  is  depressed  at  the  point  where  the  pressure  is 
exercised,  only  to  flow  back  farther  away. 

The  German  engineers  who  have  studied  this  question  with 
much  care,  Messrs.  Weber,  Winckler  and  Zimmermann,  have  ad- 
mitted, without  ever  having  demonstrated  it,  that  the  pressure,  P, 
of  the  ballast  per  unit  of  surface  of  the  cross  tie  which  it  supports 
is,  at  each  point,  in  direct  ratio  with  the  sinking,  Y,  of  the  latter. 
They  thus  place  P  =  C  Y,  an  expression  in  which  C  is  a  coefficient 
depending  upon  the  qualities  of  the  ballast,  invariable  for  the  rest, 
and  whose  numerical  value  is  determined  by  experience. 

For  Y  =  1  cm,  we  have  P  =  C.  Consequently,  it  is  the  pres- 
sure in  kilograms  on  the  unit  of  surface  (square  centimeters)  neces- 
sary to  produce  a  sinking  of  1  cm,  and  its  value  introduced  into  the 
calculation  takes  the  name  of  coefficient  of  ballast. 

The  hypothesis  of  the  sinking  proportional  to  the  pressure 
can  only  be  admitted  within  the  limits  of  elastic  deformations. 
The  statement  of  the  proportionality  of  the  sinking  and  of  the  pres- 
sure in  certain  limits,  the  determination  of  the  latter  as  well  as 
the  numerical  determination  of  the  coefficient  of  ballast,  have  given 
occasion,  on  the  part  of  German  engineers,  for  researches  whose 
results  are  the  following: 

(a)     The  results  of  experiments  agree  quite  closely  with  the 


MOVEMENTS    TO   WHICH    TRACK    IS    SUBJECTED.  39 

supposition  that  the  pressure  on  the  unit  of  surface  is  in  direct 
proportion  with  the  measure  of  the  sinking. 

(b)  With  a  subsoil  supposed  to  be  good,  the  magnitude  of  the 
coefficient  of   ballast  has   been  found,   for  gravel   ballast    (without 
metalled  bed)  C  —  3;  for  gravel  ballast  (with  metalled  bed)  C  =  8; 
for  ballast  of  small  stones  and  scoria?,  C  =  5. 

(c)  Loads,  such  as  are  found  in  regular  operation,  produced, 
almost    exclusively,    elastic    flexures.      The    permanent    deflections, 
which  have   been   observed,   probably  have   the  effect  produced   by 
repetition  of  dynamic  actions  as  their  cause. 

(d)  The  sinking  observed  under  a  load  in  motion,  at  speeds 
varying  from  40  to  60  kilometers   (24.85  to  37.28  miles)   per  hour, 
were  not  much  greater  than  the  sinking  observed  under  the  same 
load  in  a  state  of  repose. 

All  this  very  ingenious  theory  errs  in  the  premises,  because 
its  authors  have  admitted,  as  an  axiom,  that  a  loaded  cross  tie 
should  have  a  bearing  over  its  whole  length.  The  experiment  made 
with  composite  cross  ties,  whose  bed  on  the  ballast  is  well  defined, 
and  which  bends  little,  allows  us  to  pronounce  on  this  point  with- 
out possible  controversy.  The  pressure  which  the  rail  transmits 
to  the  ballast  by  the  intermediary  of  the  cross  tie  is  exercised 
only  on  a  very  limited  zone  of  support,  a  zone  which  does  not  exceed 
13.78  in.  on  both  sides  of  the  point  of  application  of  the  load.  The 
German  engineers  believed  that  this  zone  of  influence  of  loads  was 
of  tolerably  large  extent,  for  they  have  fixed  the  length  of  cross  ties 
at  8  ft.  10.3  in.  and  recommended  the  employment  of  pieces  as 
long  as  possible.  It  is  the  conclusion  at  which  Mr.  Ast,  notably, 
has  arrived  in  the  fifth  section  of  the  International  Congress  of 
Railways,  in  a  memorandum  on  track: 

"A  better  means  for  distributing  the  given  load  on  the  greatest 
possible  number  of  cross  ties,  and,  consequently,  on  the  greatest 
possible  surface  of  ballast,  consists  in  the  reduction  of  the  spacing 
of  the  cross  ties  and  in  increasing  their  surface  of  support.  These 
two  measures  have,  however,  their  limits;  the  first  because  it  is 
necessary  to  preserve  the  possibility  of  tamping,  the  second  because, 
on  the  one  hand,  the  width  of  ties  cannot  be  too  great,  if  one  wishes 
to  be  able  to  tamp  well  underneath,  and  because,  on  the  other  hand, 
the  length  which  can  be  conveniently  given  to  them  depends  on 
the  gage.  The  prolongation  of  ties  can  only  bear,  in  fact,  on  the 
parts  situated  at  the  exterior  of  the  two  lines  of  rails.  When  this 
prolongation  surpasses  a  certain  limit,  the  loads  on  the  rails,  which 
act  on  the  interior  of  the  gage,  provoke  a  super-elevation  of  their 


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46  TRACK  DEFORMATIONS. 

extremities,  and  the  parts  of  that  length  In  excess  no  longer  haye 
a  bearing." 

This  last  fact  has  been  verified;  Mr.  Ferry,  Sub-Engineer  of 
the  P.  L.  M.  Co.,  has  obtained  curves  of  deformation  of  long  cross 
ties  8  ft.  6.4  in.  to  8  ft.  10.3  in.  placed  in  resistant  ballast  (broken 
stone),  on  which  the  extremities  are  seen  raised  up  above  the 
axis  of  the  part  not  loaded.  The  experiments  performed  show  also, 
although  in  a  less  clear  manner,  this  fact:  the  more  wet  the  bal- 
last is,  the  more  gentle  is  the  slope  of  the  extremities,  for  the  pres- 
sure is  transmitted  over  a  greater  surface;  on  the  contrary,  when 
the  ballast  is  dry,  the  ends  of  the  cross  tie  have  a  tendency  to 
raise  up. 

Therefore  it  is  impossible  to  diminish  the  sinking  of  ties  by 
increasing  their  length;  moreover,  independent  of  its  uselessness, 
this  prolongation  produces  a  grave  disadvantage,  for  it  increases 
the  bending.  It  is  not  by  this  means  that  we  should  seek  to  re- 
duce the  deformation  of  the  track,  but  by  widening  the  cross  tie, 
by  concentrating  the  material  about  the  points  of  support,  and 
above  all,  by  augmenting  its  moment  of  inertia. 

The  composite  ties  have  an  effective  length  of  8  ft.  2.4  in.,  but 
the  useful  length,  that  is  to  say  that  comprised  between  the  two 
extremities  of  the  blocks,  is  no  more  than  7  ft.  2.64  in.;  it  is  at 
once  seen  in  Fig.  12,  Nos.  2,  4,  6,  that,  reduced  to  7  ft. 
2.64  in.,  the  cross  tie  would  still  have  a  less  flexure.  This  last 
consideration,  joined  with  the  examination  of  the  curves  of  de- 
formation of  the  ties  of  8  ft.  6.36  in.,  has  led  to  research  as  to 
what  ought  to  be  the  length  of  a  tie  and  of  its  tamped  bed  in  order 
to  reduce  the  flexure  in  the  greatest  measure  possible.  The  long 
ties  affect  the  deformation  pointed  out  above  with  concavity  di- 
rected upward;  the  short  cross  ties  ought,  on  the  contrary,  to  be 
deformed  according  to  a  convex  curve;  between  the  two  there 
ought  then  to  be  such  a  length  that  the  deformed  curve  approaches 
a  right  line.  We  propose  to  make  that  research  which  appears 
to  us  to  present  a  great  practical  interest. 

But  before  entering  upon  this  new  order  of  ideas,  it  would 
have  been  interesting  to  present  the  theory  of  the  cross  tie  which 
results  from  these  experiments,  and  which  is  very  far  removed 
from  that  admitted  by  Winckler;  it  would  have  been  established 
that  theory  was  in  accord  with  experiment,  that  is  to  say,  that 
the  curve  found  experimentally  was  quite  like  that  of  a  beam 
placed  on  an  elastic  support,  but  less  elastic  than  it,  loaded  at  two 
points  with  loads  exercising  their  influence  on  a  predetermined 


MOVEMENTS   TO   WHICH    TRACK   IS   SUBJECTED.  47 

zone  of  support.  It  would,  then,  be  a  question  of  determining, 
with  that  hypothesis,  the  reactions  of  this  support,  and  of  demon- 
strating that,  in  the  central  part,  the  cross  tie  was  found  to  be 
submitted  to  a  counter  pressure.  Unfortunately,  time  was  want- 
ing for  examining  this  problem  of  elasticity,  which  is  long  and 
difficult;  the  elements  acquired  will  doubtless  permit  of  giving  the 
solution  after  a  brief  delay. 

In  the  meantime,  we  desired  to  determine  the  coefficient  of 
ballast  in  the  experiments  carried  on,  this  coefficient  being  de- 
fined, as  has  been  stated  above.  The  axle  loading  being  26,455  Ibs., 
the  load  on  the  rail,  that  is  to  say  the  load  on  the  tie,  was  about 
13,228  Ibs.  (for  it  is  admitted  that  on  a  track  with  rigid  rails  the 
maximum  load  on  a  given  cross  tie  is  about  50  per  cent,  of  the  load 
on  the  axle) ;  the  13,228  Ibs.  ought  to  be  distributed  between  the 
two  composite  blocks  proportionately  to  their  sinking.  The  block 
on  the  side  of  the  short  radius  will  thus  support  7,945  Ibs.,  and 
that  on  the  side  of  the  long  radius  5,282  Ibs.  The  mean  sinking 
of  the  first  block  being  .052  in.  and  that  of  the  second  .048  in. 
(Experiments  of  July  30,  1903,  Fig.  11,  No.  6)  the  pressure 
of  the  ballast  per  unit  of  surface  will  be  29.15  Ibs.  per  sq.  in.  on 
the  side  of  the  short  radius,  and  19.34  Ibs.  per  sq.  in.  on  the  side 
of  the  long  radius.  The  coefficient  of  ballast,  that  is  to  say,  the 
pressure  per' unit  of  surface  capable  of  producing  a  sinking  of 
"/ei  in.  in  the  ballast  and  the  subsoil  considered  would  be  160.14  Ibs. 
per  sq.  in.,  that  is  to  say  three  times  higher  than  that  adopted  by 
the  German  engineers.  The  ballast  and  subsoil  considered  were, 
in  fact,  of  mediocre  quality.  It  is  then  supposable  with  some  reason 
that  with  a  good  ballast  and  a  very  solid  roadbed  the  coefficient 
of  ballast  will  be  at  least  284.5  Ibs.  per  sq.  in.  The  precise  experi- 
ments which  we  will  next  undertake  will  permit  of  elucidating  this 
point  more  completely. 


CHAPTER  III. 

LENGTH  TO  GIVE  TIES  AND  TAMPED  BED. 

After  proving  that  the  most  advisable  length  for  a  tie  for  dimin- 
ishing its  flexure  ought  to  be  in  the  neighborhood  of  7  ft.  2.64  in. 
I  desired  to  determine  the  latter  experimentally  with  wood  ties  of 
different  lengths,  tamped  unequally,  and  placed  on  a  level  and  on 
straight  line,  in  order  to  avoid  all  chance  of  error. 

Mr.  Ferry,  Sub-Engineer  of  the  P.  L.  M.  Co.,  wished  expressly 
to  aid  me  with  his  counsels,  and  to  build  an  experimental  side  track. 
This  track,  placed  at  the  extremity  of  the  cul-de-sac  of  the  track 
for  unloading  animals  at  the  station  of  Bourg,  P.  V.,  was  isolated 
from  the  switching  of  that  station,  so  that  we  could  easily  proceed 
with  all  the  trials  without  being  obliged  to  abandon  them  and  then 
resume  them,  which  causes  the  loss  of  much  time  and  interrupts 
their  course. 

The  ties  on  trial,  wood,  steel  and  composite,  were  always  placed 
at  the  same  point,  about  6.56  ft.  from  the  neighboring  ties;  the 
rail  was  raised  up  on  it  25/64  in.  above  them;  thus  the  axle  load, 
13.22  net  tons,  rested  entirely  on  the  experimental  piece.  In  order 
to  avoid  raising  of  the  track  at  the  extremity  of  the  cul-de-sac, 
the  extremity  of  the  rails  was  loaded  and  held  in  place.  A  tent 
was  set  over  the  working  place  to  completely  shelter  the  track  and 
withdraw  it  from  atmospheric  influences;  in  this  manner,  the  bal- 
last, formed  of  fine  gravel,  and  the  subsoil,  were  always  found 
in  the  same  hygrometric  conditions.  A  tie  was  placed  at  the  pre- 
determined site,  and  at  the  aforesaid  height,  with  reference  to  the 
neighboring  cross  ties;  for  there  were  buried  in  the  roadbed  in 
excavation,  on  both  sides  of  the  track,  two  strong  stakes  4.92  ft. 
deep,  and  between  them  a  rigid  string  was  extended,  in  order  to 
determine  the  position  of  the  axis  of  the  piece  and  the  height  of 
the  rail. 

The  parts  marking  the  surface  of  the  tie  in  a  free  state  were 
measured  by  means  of  the  rule  described,  as  has  been  explained  in 
the  preceding  tests.  Two  readings  were  taken  by  means  of  the 
wedge  gage  provided  with  a  runner,  in  order  to  be  able  to  esti- 


LENGTH  TO  GIVE  TIES  AND   TAMPED  BED.  49 

mate  the  hundredths  of  a  millimeter.  The  wood  ties  were  provided, 
as  before,  with  screws  with  square  heads,  invariably  fixing  the  points 
of  measurement;  but  in  order  to  assure  the  horizontality  of  the 
wedge,  there  was  placed  in  front  of  the  first  screws  other  similar 
screws  provided  with  a  notch  for  guiding  it. 

The  vehicle,  loaded  with  care  with  pieces  of  rails,  weighing 
26.46  net  tons,  was  mounted  on  two  axles;  when  the  first  reading 
was  finished,  it  was  brought  close  to  the  cross  tie,  at  a  point  of  the 
rail  determined  by  the  position  of  the  wooden  wedges.  It  was  al- 
lowed to  stand  for  an  hour,  and  two  readings  were  made  on  each 
point,  as  in  the  other  tests.  Each  reading  was  controlled  with  care 
and  checked  by  other  experimenters  when  the  difference  attained 
two  hundredths  of  a  millimeter.  The  mean  of  the  figures  was  taken, 
which  approached  consequently  nearly  to  one  hundredth  of  a  milli- 
meter. The  vehicle  was  removed,  the  beam  recovered,  and  the  new 
position  of  its  axis  was  ascertained  by  two  new  readings.  The  dif- 
ference between  the  figures  of  the  original  position  without  load  and 
of  the  position  with  load,  gave  the  total  sinking;  the  difference 
between  the  latter  situation  and  the  new  position  of  the  piece  with- 
out load,  determined  the  elastic  sinking.  The  permanent  sinking 
resulted  from  the  difference  between  these  figures.  In  Nos.  1  to  12 
of  Fig.  12,  which  displays  these  experiments,  the  full  lines  represent 
the  position  of  the  original  axis  and  of  the  deformed  axis;  the  dotted 
line,  the  axis  after  recovery  of  the  beam. 

The  experiments  were  made  with  wood  ties  of  different  lengths 
with  variable  tamped  beds,  and  with  the  composite  tie  and  the  steel 
tie  of  the  state. 

Wood  tie  8  ft.  6.36  in.  by  8.66  in.  (Nos.  1  and  2,  Fig.  12.)  — 
We  commenced  with  an  oak  cross  tie  well  squared,  8.66  in. 
wide,  5.51  in.  thick  and  8  ft.  6.36  in.  long.  The  tamping  extended 
over  its  whole  length.  The  beam  was  deformed  under  the  load  ac- 
cording to  the 'curves  in  Nos.  1  and  2  of  Fig.  12.  Their  form  is 
convex,  raised  towards  the  center,  with  a  tendency  to  uplift  at  the 
extremities,  the  pressure  being  less  strong  at  those  points.  The 
sinking  is  more  pronounced  on  the  left  side,  .16  in.  by  .18  in.,  than 
on  the  right  side,  .154  in.  by  .173  in.,  by  reason  of  the  greater 
solidity  of  the  subgrade.  At  the  center  it  is  only  .10  in.  and  .12  in. 
The  elastic  upraising  is  greater  in  the  first  test  than  in  the  second, 
without  doubt  because  the  tamping  had  been  more  compact;  it  at- 
tains, in  fact,  .091  in.  in  the  first  case  and  .06  in.  second.  The 
greatest  compression  is  found  on  the  exterior  side  of  the  rail  (first, 
test  .185  in.,  second  test  .18  in.),  which  is  explained  by  the  reac- 


50  TRACK  DEFORMATIONS. 

tion  of  the  ballast,  which  rights  the  cross  tie  and  inclines  it  towards 
the  extremities. 

Tie  8  ft.  6.36  in.  by  8.66  in.,  tamped  at  the  end  at  15.75  in.  each 
side  of  the  rail.  (No.  3,  Fig.  12.) — The  same  tie,  tamped  at  its 
extremities  and  at  15.75  in.  on  each  side  in  the  interior,  served  for 
this  test.  The  tamping  was  limited  by  two  angles  fixed  to  the  bot- 
tom of  the  tie  at  the  extreme  points  of  the  tamping.  The  form  at- 
tained is  that  of  the  basin  observed  at  St.  Etienne-du-Bois;  the 
bottom  is  slightly  raised  in  comparison  with  the  left  side;  the  ex- 
tremity of  the  right,  resting  on  a  more  solid  foundation,  is  raised 
more.  The  compression  is  maximum  in  the  interior  of  the  track; 
the  sinking  attains  .185  in.  to  the  left  and  .18  in.  to  the  right.  The 
elastic  uplift  has  taken  place  according  to  a  slightly  concave  curve, 
like  that  which  is  generally  observed  at  the  working  places  of  cross 
tie  renewals.  It  is  sensibly  equal  to  that  stated  above,  about  .063  in., 
the  mean  permanent  sinking  being  .106  in. 

Tie  7  ft.  6.96  in.  long,  tamped  over  15.75  in.  on  each  side  of 
the  rail.  (No.  4,  Fig.  12.) — The  same  tie  reduced  to  7  ft.  6.96  in. 
and  tamped  over  15.75  in.  on  each  side  of  the  rail  was  the  object  of 
a  test.  The  tamping  was  limited  as  above  by  angles.  The  curve 
took  the  form  of  a  basin  more  flattened  than  the  preceding,  with 
raising  in  the  central  part,  the  pressure  tending  to  be  distributed 
equally  over  the  ballast.  The  total  sinking  is  less  in  consequence 
of  this  fact;  it  scarcely  reaches  .150  in.  while  it  exceeds  .18  in. 
in  the  preceding  case.  The  elastic  uplift  is  consequently  a  little 
less.  The  maximum  pressure  is  exercised  in  the  interior  and  near 
the  rail. 

Tie  7  ft.  6.96  in.  long,  with  tamped  bed  15.75  in.  and  21.65  in. 
{No.  5,  Fig.  12.) — This  tie,  7  ft.  6.96  in.  long,  was  unsymmetrically 
tamped  15.75  in.  at  the  extremities  and  21.65  in.  in  the  interior. 
The  total  sinking  is  not  greater  than  in  the  preceding  case;  the 
pressure  is  distributed;  the  center  is  raised  up,  being  little  more 
than  with  the  symmetrical  tamping,  which  depends  on  the  fact  that 
it  is  naturally  more  supported.  The  elastic  uplift  is  made  as  above; 
the  beam  is  righted  so  to  speak  parallel  with  itself. 

Wood  ties  7  ft.  3  in.  long,  with  tamping  13.78  in.  on  each  side 
of  the  rail.  (No.  6,  Fig.  12.)— The  same  tie,  reduced  to  7  ft. 
3  in.  long,  was  tested  with  two  different  repetitions  with  a  sym- 
metrical tamping  13.78  in.  long  on  each  side  of  the  rail.  The  curva- 
ture of  the  elastic  line  diminishes  (No.  6,  Fig.  12);  the 
beam  is  lowered,  so  to  speak,  parallel  with  itself.  The  pressure  is- 
•equally  distributed  over  the  ballast.  The  total  sinking  seems  greater, 


LENGTH  TO  GIVE   TIES  AND  TAMPED  BED.  51 

which  holds  with  tamping  which  has  been  more  or  less  condensed; 
but  the  elastic  uplift,  which  is  only  to  be  considered,  is  nearly  the 
same,  to  some  tenths  of  a  millimeter. 

Wood  tie  7  ft.  0.6  in.,  with  unsymmetrical  tamping.  (No.  9, 
Fig.  12.) — The  unsymmetrical  tamping  of  this  same  tie,  which  is 
7  ft.  0.6  in.  long,  because  it  was  effected  over  12.6  in.  at  its  ex- 
tremities and  over  14.96  in.  towards  the  interior,  raises  the  pre- 
ceding curve  toward  the  center,  a  curve  which  is  convex  at  the 
middle  and  inclined  towards  the  extremities. 

The  pressure  is  exercised  more  towards  the  exterior,  for  the 
reason  that  the  beam  is  sustained  on  the  side  of  its  center;  it  is 
distributed,  however,  better  than  in  the  first  cases  examined;  the 
total  sinking  is  always  nearly  the  same  as  the  elastic  uplift.  The 
latter  preserves  the  same  value  approached  after  a  second  test. 
The  beam  returns  parallel  with  itself. 

Wood  tie  6  ft.  11.04  in.,  with  unsymmetrical  tamping.  (No.  8, 
Fig.  12.) — This  tie  was  6  ft.  11.04  in.  long,  with  an  unsymmetrical 
tamped  bed  of  11.81  in.  at  the  extremities,  and  of  15.75  in.  towards 
the  center.  It  takes  a  convex  form  under  the  load,  as  in  the  pre- 
ceding test.  The  maximum  sinking,  very  pronounced  towards  the 
extremities,  is  more  important  because  the  latter  have  been  brought 
more  closely  to  the  point  of  application  of  the  pressure.  The  elastic 
uplift  is  the  same,  and  is  made  nearly  parallel  to  the  axis  of  the 
deformed  beam.  After  three  successive  tests,  the  second  after  two 
hours,  the  third  after  four  hours,  the  lowering  has  scarcely  in- 
creased; the  beam  is  always  deformed  parallel  with  itself  and  the 
elastic  uplift  remained  what  it  was  after  the  first  test. 

The  composite  tie  (No.  10,  Fig.  12)  behaved  as  in  all  earlier 
experiments;  it  was  lowered  nearly  parallel  with  itself  without 
apparent  deformation.  It  reascended  the  same.  The  total  sinking 
is  nearly  the  same  as  for  the  wood  ties;  the  elastic  uplift  is  also  the 
same.  The  beam  is  righted  according  to  a  plane  slightly  inclined 
on  the  side  where  the  earth  was  the  more  solid. 

The  metallic  tie  of  the  state  system  (Nos.  11  and  12,  Fig.  12) 
was  tested  with  two  tamped  beds,  the  first  over  its  entire  length, 
the  second  over  its  breech,  and  15.75  in.  long  in  the  interior  of  the 
track. 

In  the  first  case  the  deformation  has  occurred  in  a  very  irrsg- 
ular  fashion,  following  a  convex  form  in  the  center  with  the  ordi- 
nary sinking;  the  beam  is  uplifted  according  to  a  plane  inclined 
to  the  left.  It  seems,  at  first  sight,  to  have  no  very  regular  resist- 
ance in  all  its  sections,  and  to  be  bound  to  be  deformed  quite  rapidly. 


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58  TRACK  DEFORMATIONS. 

In  the  second  case,  the  curve  is  more  regular  and  is  concave 
towards  the  center.  The  beam  is  righted  according  to  the  profile 
of  a  catenary,  which  ought  to  give  it  in  time  a  permanent  deforma- 
tion and  produce  a  diminution  of  the  track  gage. 

In  all  the  experiments  which  have  just  been  related,  the  rela- 
tive sinking  of  the  ties  with  each  other  has  not  been  sought  for, 
since  that  question  was  solved  on  the  main  track  from  Bourg  to 
Saint-Amour,  and  since  the  necessity  for  a  tamped  bed,  executed 
in  a  more  or  less  firm  manner,  in  one  test  or  the  other,  and,  as  a 
consequence,  irregularly  settled,  render  all  comparison  illusory. 

But  the  following  points  should  be  retained  from  the  study 
which  has  been  made: 

(a)  The  long  ties,  8  ft.  6.36  in.  to  7  ft.  6.6  in.,  take,  under  the 
load,  the  form  of  a  basin,  with  the  bottom  slightly  raised   in  the 
center. 

(b)  The  short  ties,  7  ft.  0.6  in.  to  6.5  ft.,  are  deformed  accord- 
ing to  a  curve,   convex  or  otherwise,  and   inclined  toward  the  ex- 
tremity. 

(c)  The  ties  between  7  ft.  0.6  in.  and  7  ft.  2.64  in.  are  lowered 
parallel  with  themselves  without  sensible  curvature. 

(d)  The  unsymmetrical  tamping  raises  the  curve  towards  the 
center;  a  very  feeble  lack  of  symmetry  reacts  very  clearly  in  this 
direction. 

(e)  It  is  possible,  then,  by  increasing  the  rigidity  of  a  cross 
tie,   notably   by   concentrating  the   material  about  the   supports,  to 
recuce  its  sinking  to  the  quantity  which  is  intended  as  a  limit,  and 
its  flexure  in  such  measure  as  one  would  wish. 

(f)  The  permanent  sinking  of  the  ballast  is  variable  accord- 
ing to  the  case,  but  the  elastic  sinking',  the  only  one  there  is  reason 
to  consider,  is,  so  to  speak,  constant,  whatever  be  the  length  and 
type  of  the  cross  tie  adopted.     The  deformation  is  slowly  produced 
and  augments  with  time. 

DYNAMIC    EXPERIMENTS. 

The  results  obtained  under  moving  loads,  at  the  passage  of  sev- 
eral trains  traveling  with  different  speeds,  have  always  been  the 
same,  comparatively,  as  those  obtained  in  the  static  state.  They 
are  always  less,  from  10  to  20  per  cent.,  than  the  latter,  and  the 
difference  observed  between  the  flexure  of  the  wood  ties  and  of  the 
composite  ties  supporting  the  same  rails  is  maintained,  the  latter 
being  less  deformed,  and  sinking  less  than  the  former.  The  refer- 
ence marks  were  at  first  placed  at  5.12  in.  on  the  interior  of  the  two 


LENGTH  TO  GIVE  TIES  AND  TAMPED  BED.  59 

rails,  points  where  the  maximum  deformation  in  the  static  state  is 
produced,  then  on  five  points  equally  distributed  over  the  length  of 
the  pieces.  The  figures  have  always  been  found  less  than  those  of 
the  static  state  (the  mean  .05  in.  for  ties  of  wood,  .035  in.  for 
composite  ties);  the  composite  tie  descended  parallel  with  itself, 
while  the  wood  tie  is  deformed  according  to  the  curves  described 
cases.  The  deformation  of  the  material  is  made  slowly,  and  as 
above. 

All  the  experiments  which  we  have  made,  as  well  as  those  which 
have  been  previously  realized  by  Mr.  Ferry,  lead  to  the  same  con- 
clusion; dynamic  actions  produce  less  effect  than  static  actions;  in 
order  to  obtain  the  maximum  deformation,  it  is  then  sufficient  to 
examine  what  occurs  in  the  static  state. 

The  apparatus  for  measurement,  which  is  very  simple,  and  dis- 
posed in  such  a  manner  as  not  to  be  influenced  in  the  course  of 
the  trial,  cannot  be  considered  faulty.  The  rod  which  sustains  the 
spring  is  buried  to  4.92  ft.  in  the  soil;  it  should  be  able  to  rise  up 
vigorously  under  the  load,  which  would  increase  the  bending  figures, 
but  it  cannot  descend  under  that  influence.  As  to  the  spring,  it 
will  not  grip  against  the  glass  plate,  but  it  will  slide  against  it. 
Besides,  Mr.  Ferry  has  shown  that  the  figures  of  deformation  were 
the  same  in  the  static  state,  whether  they  be  observed  by  means 
of  the  rule  or  by  means  of  the  spring  register.  The  results  orb- 
tained  under  a  moving  load  ought,  then,  to  be  considered  as  exact. 

It  is  necessary,  then,  that  the  dynamic  actions  be  exercised 
with  less  intensity  than  the  static  actions.  There  is,  we  believe, 
a  law  which  ought  to  be  nearly  general,  except  in  certain  particular 
much  more  slowly  as  the  latter  is  more  rigid,  and  as  the  mechanical 
actions  take  place  in  a  short  time.  A  spring  registers  slowly  the 
forces  to  which  it  is  submitted;  at  the  same  time,  preserved  from 
their  effect,  it  is  distended  no  less  slowly,  and  retakes  its  primitive 
form  in  a  time  of  definite  duration.  One  can  walk  without  leav- 
ing an  imprint  on  a  moving  soil  of  weak  consistency,  when  walking 
rapidly;  the  deformation  has  not  had  time  to  be  produced.  If,  on 
the  contrary,  one  stood  still  on  the  same  soil,  the  latter  would  be 
deformed  more  or  less  rapidly,  according  to  its  degree  of  resistance. 

All  the  known  facts  confirm  this  law  of  deformation,  which  can 
be  considered  as  general.  Without  doubt,  it  is  admitted  that  in 
metallic  work,  dynamic  actions  increase  static  actions  by  70  per 
cent.;  but  that  does  not  weaken  in  any  way  the  law  which  we  have 
derived  from  these  experiments. 

The  tie  on   which  the  flexure  has  been   studied  does  not  take 


60  TRACK  DEFORMATIONS. 

the  proper  deformation  which  it  should  have  under  the  action  of 
loads,  but  it  undergoes  that  of  the  ballast,  which  serves  for  its 
support,  and  of  the  bed  of  the  ballast.  It  results  that  its  deforma- 
tion is  limited  by  that  of  the  material  which  sustains  it.  This 
material  acts  on  the  tie  after  the  manner  of  a  powerful  spring,  which 
slowly  registers  the  forces  which  it  receives,  and  which  does  not 
attain  to  registering  them  completely  when  they  arrive  in  too  short 
a  time.  In  particular,  the  shocks  which  are  the  consequence  of 
dynamic  actions,  and  which  are  only  susceptible  of  increasing  the 
flexures  in  the  static  state,  cannot  produce  this  effect,  because  they 
act  in  too  short  a  time  for  influencing  the  spring. 

It  is  not  the  same  as  a  piece  of  metallic  work,  which,  not  being 
sustained,  obeys  all  the  vibrations  it  receives,  and  which  are  so 
much  the  more  intense  as  they  are  due  to  a  more  violent  and  shorter 
shock.  Such  is  the  chord  of  an  instrument,  which,  taut,  enters  into 
vibration  under  an  instantaneous  influence,  for  example,  the  sound 
rendered  by  a  neighboring  instrument.  Shocks  have  thus  an  im- 
portant action  on  a  metallic  floor,  which  registers  them  by  reason 
of  its  situation  and  their  instantaneousness;  but  they  have  not  any 
on  a  piece  sustained  by  an  elastic  material  but  reacting  by  its  mass 
after  the  fashion  of  a  spring.  It  is  possible  that  the  materials  of 
the  track,  the  rails,  for  example,  do  not  obey  this  last  law,  but  the 
experiments  made  up  to  this  time  permit  of  no  conclusion  either 
in  one  direction  or  the  other. 

Apart  from  the  transverse  movement,  which  we  have  just  been 
studying,  the  track  is  submitted  to  a  lateral  movement,  which  is 
explained  as  a  sliding  movement,  and  often  causes  derailments. 
Weber  has  determined  the  maximum  values  of  the  sliding  movement 
of  the  track  which  are  produced  in  the  course  of  normal  traffic. 
His  tests  have  demonstrated  that  in  alinement  it  produces  displace- 
ment which  may  reach  %  in.  for  the  base  of  the  rail,  and  .28  in. 
for  the  head. 

Engesser  has  proved  that  it  would  suffice  for  main  tracks,  to 
take  0.15  to  0.25  G  (G  load  on  wheel)  as  the  ordinary  value  of  the 
horizontal  force. 

But  if  the  greatest  vertical  pressures  on  the  track  are  pro- 
duced by  the  overloaded  axles,  the  greatest  horizontal  pressures 
are  due  to  the  unloaded  axles.  The  latter  have  their  greatest  effect 
when  the  ballast  is  the  most  unsettled,  ttfat  is  to  say,  when  it  has 
just  been  changed  or  renewed. 

It  was  then  placed  under  the  most  unfavorable  conditions;  the 
experimental  ties  were  arranged  as  follows:  Wood  ties  and  steel 


LENGTH  TO  GIVE  TIES  AND   TAMPED  BED.  61 

ties  in  a  switching  track  at  the  Bourg  station.  They  were  isolated 
from  the  neighboring  ties,  either  by  superelevating  them  and  re- 
moving the  plates  from  the  neighboring  pieces,  or  again  by  with- 
drawing the  latter  from  the  track;  in  this  manner  it  was  cer- 
tain that  the  cross  tie  under  experiment  alone  sustained 
the  weights  which  were  placed  on  it.  Besides,  the  shoulder 
plate  of  the  cross  tie  under  experiment  was  replaced  by  an  ordi-" 
nary  flat  plate,  and  the  screw  spikes  were  withdrawn  so  that  the 
cross  tie  could  slide  under  the  rail,  but  in  order  to  diminish  the 
friction,  the  surfaces  in  contact  were  greased. 

This  done,  the  tie  was  pushed,  being  thus  rendered  independent, 
and  without  load,  by  means  of  the  Collet  declimeter,  installed,  on 
the  one  hand,  against  the  extremity  of  the  piece,  and  on  the  other 
hand  against  a  very  solid  wall.  Then  the  same  tie  was  loaded  by 
means  of  an  axle  of  6.61  net  tons,  and  the  experiment  pushed  in 
the  two  cases  up  to  the  moment  when  a  displacement  of  .8  in.  was 
obtained,  at  which  the  track  can  be  considered  as  out  of  service. 

The  results  of  these  experiments  .are  given  in  the  table  below: 

, For  a  displacement  of  .8-in. x 

, Without  load. x     With  load. 

Composite  tie,   in  the  free  state From  4,189  to  5,291  Ibs.     15,212  IDS. 

Wood  tie,  in  the  free  stateT 220  Ibs.  11,684    " 

Steel  tie,  in  the  free  state 1,102    "  7,496    lk 

The  composite  tie  offers  a  resistance  24  times  greater  than  that 
of  the  wood  tie  when  it  is  not  loaded,  that  is  to  say,  when  this  re- 
sistance presents  its  weakest  value.  When  it  is  loaded  with  an  axle 
of  six  metric  tons,  its  resistance  to  sliding  is  still  greater  by  nearly 
3,307  Ibs.  than  that  of  the  wood  tie.  This  is  not  true  of  the  steel 
tie;  the  latter,  at  first  more  resistant  than  the  wood  tie,  not  carry- 
ing any  load,  becomes  less  under  the  load,  which  appears  to  arise 
from  the  less  friction  of  the  ballast  against  the  metallic  body. 

If  only  the  two  ties,  respectively  the  wood  and  the  composite 
one,  are  considered,  it  is  observed  that  their  resistance  to  sliding 
being  respectively  about  220  Ibs.  and  4,409  Ibs.  without  load,  there 
remains  for  the  resistance  under  the  load  of  6.61  net  tons,  11,464  Ibs. 
for  the  first  and  10,802  Ibs.  for  the  second.  The  friction  which 
operates  against  the  sliding  is  thus  proportional  to  the  weights  and 
not  to  the  frictional  surface  or  the  substances  having  the  same 
adherence  with  the  ballast.  Mr.  Ferry  has  found  that  for  wood 
ties  this  resistance  varies  from  50  to  80  per  cent,  of  the  overload- 
ing, 50  per  cent,  when  the  pieces  are  smooth,  freshly  creosoted,  -80 
per  cent,  on  the  contrary  when  they  are  rough,  and  when  the  super- 
ficial layer  of  creosoting  has  been  cut  by  the  rubbing  against  the 


152  TRACK  DEFORMATIONS. 

ballast.  He  has  equally  demonstrated  that  the  addition  of  angles 
under  the  cross  tie,  in  a  word  of  projections  able  to  give  support 
against  the  ballast,  sensibly  increased  the  resistance  to  sliding  by 
about  20  per  cent,  of  the  overload. 

In  the  particular  case,  the  wood  ties  being  experimented  with, 
having  been  placed  for  a  long  time  in  the  track,  ought  to  offer  a 
maximum  adherence;  the  coefficient  reached  80  per  cent,  of  the 
overload,  that  is  to  say,  about  10,582  Ibs.,  nearly  the  figure  given 
^above,  11,464  Ibs.  For  the  composite  tie  placed*  in  the  track  at  the 
same  moment  of  the  experiment,  the  adherence  was  not  great, 
scarcely  60  per  cent;  it  was  then  7,937  Ibs.,  to  which  it  was  neces- 
sary to  add  the  20  per  cent,  due  to  the  cross  bars,  2,646  Ibs.  The 
total  resistance  would  thus  be,  theoretically,  from  10,582  Ibs.  to 
220  Ibs.,  near  the  figure  obtained.  The  observations  of  Mr.  Ferry 
are  then  completely  confirmed. 

Again,  it  ought  to  be  remarked  that  the  thickness  of  the  cross 
bar  or  of  the  roughness  ought  to  be  relatively  small,  to  have  its 
full  efficiency.  A  centimeter  of  protuberance  suffices  and  it  is 
•easily  conceived,  for  the  tamped  bed  has  no  compactness,  and  only 
offers  consequently  resistance  in  its  upper  part.  The  maximum  use- 
ful effect  is  thus  produced  on  the  surface  of  the  ballast;  an  increase 
in  the  relief  of  the  cross  bars  does  not  produce  an  increase  in  the 
resistance.  That  results  from  experiments  made  by  the  P.  L.  M.  Co., 
and  explains  the  results  which  have  been  found  with  a  tie  provided 
with  cross  bars. 


CHAPTER  IV. 

DEFORMATION  OF  THE  TRACK. 

The  sliding  of  the  track,  which  is  one  of  the  most  frequent 
•deformations,  and  the  most  prejudicial  to  operation,  is  not,  however, 
the  principal  one;  others  are  produced  of  a  permanent  kind, 
which  cause  disorders  in  the  track.  While  not  primarily  as 
grave,  they  occasion  by  their  repetition  serious  difficulties. 
Among  them  may  be  mentioned  creeping  of  the  track,  narrow- 

x 

ing  of  the  gage  on  tangents,  or  its  spreading  on  curves;  the 
compression  of  the  wood  at  the  supports,  tearing  out  the  screw 
spikes,  and,  finally,  the  shock  which  is  produced  right  at  the  joint, 
and  which  causes  the  dislocation  of  the  track  and  the  vertical  defor- 
mation of  the  rail. 

All  these  deformations  are  caused  by  the  longitudinal  and  trans- 
verse movements  previously  described.  They  are  the  consequences 
-of  them,  to  such  a  point  that  when  these  movements  are  diminished, 
the  deformations  are  reduced  at  the  same  time. 

CREEPING  OF  THE  TRACK. 

Rolling  loads  produce,  in  the  direction  of  the  movement  of  the 
trains,  longitudinal  displacements  of  the  rails,  which  are  ordinarily 
called  dragging  or  creeping,  and  sometimes  the  entire  track  is  drawn 
along.  The  ordinary  methods  employed  for  preventing  creeping 
(notching  of  rails,  anti-creepers,  joint  plates,  angle  bars)  transmit, 
in  a  certain  measure,  the  forces  producing  the  longitudinal  pushing 
of  the  rail  to  the  fastenings  as  well  as  to  the  tie  and  to  the  ballast. 
The  movement  is  more  or  less  retarded,  and  the  advance,  whose 
effects  are  injurious,  as  I  will  show  further  along,  diminished. 

The  rails  are  subjected  in  the  longitudinal  direction  to  two 
forces  in  a  contrary  direction;  the  driving  wheels  of  the  engine 
determine  by  their  adhesion  a  reaction  on  the  rails  directed  in  an 
inverse  direction  to  the  travel;  the  carrying  wheels  of  the  engine 
and  those  of  the  other  vehicles  tend  on  the  contrary  to  push  the 
rail  ahead.  It  is  the  last  effects  which  are  predominant,  and  ex- 
perience shows  that  the  longitudinal  movement  of  rails  always  takes 
place  in  the  direction  of  the  trains  on  a  double-track  line. 


64  TRACK  DEFORMATIONS. 

But  the  longitudinal  movement  is  not  equal  in  the  two  lines  of 
rail,  even  on  tangents;  when  the  road  is  double  track  the  rail  ad- 
vances more  rapidly  in  the  line  of  rail  on  the  outside  (the  left 
line)  than  in  that  of  the  inter-track  side  (right  line).* 

It  results  that  the  joints  of  the  two  lines  of  rail  are  no  longer 
concordant;  ties,  especially  those  which  act  jointly  with  the  rail, 
for  example,  the  ties  of  the  even-joint  at  the  following  end,  are 
no  longer  placed  normally  .with  the  track;  the  gage  of  the  track 
narrows;  the  screw  spikes  lose  their  contact  with  the  base  of  the 
rail.  The  overlapping  of  the  joints,  which  in  general  are  low,  no 
longer  allows  the  fall  of  the  wheels  at  the  passage  of  the  joint  to 
be  simultaneous  on  the  two  lines  of  rails,  and  there  must  neces- 
sarily result  from  it  zig-zagging  movements  for  the  engine  and  cars. 

The  longitudinal  dragging  causes  as  an  effect  the  allowance 
for  expansion  at  the  joints  to  disappear  when  the  temperature  rises, 
the  rails,  no  longer  being  able  to  expand,  become  compressed,  and 
a  zig-zagging  movement  can  produce  a  lateral  sliding  of  the  track. 

It  is  necessary,  periodically,  to  put  the  rails  back  in  place,  and 
this  operation  is  costly;  Mr.  Ferry  estimates  it  at  $18.80  per  mile 
per  year  on  a  line  of  average  traffic.  The  longitudinal  movement 
is  therefore  of  real  importance,  and  the  principal  causes  which  deter- 
mine this  forward  movement  should  be  sought. 

Mr.  Coiiard  estimates  that  the  creeping  (Revue  des  Chemins 
de  Fer,  August,  1896)  ought  to  be  attributed  principally  to  the  shock 
of  the  wheels  at  the  passage  of  joints.  It  will  be  seen,  further  along, 
that  the  rails  deflect  at  their  extremities  at  the  passage  of  the 
wheels,  and  that  the  latter  fall  from  the  advance  rail  on  the  follow- 
ing-rail, always  more  or  less  inflected,  and  produce  a  shock  the  more 
perceptible,  the  older  the  track  is  and  the  more  deformed  the  rails 
are  vertically.  The  wheel  would  act  on  the  following-rail  after  the 
manner  of  a  wedge,  and  would  drive  it  before  it. 

This  explanation  of  the  advance  movement  is  very  proper,  and 
is  corroborated  by  a  series  of  facts  which  Mr.  Coiiard  has  put  in 
evidence  in  a  very  neat  manner. 

Thus,  the  speed  of  the  trains  increases  the  dragging;  the  latter 
is  therefore  maximum  on  the  grades.  Braking  produces  the  same 
effect,  since  sliding  friction  is  added,  and  creeping  is  very  pronounced 
at  the  limits  of  stations. 

On  curves  this  movement  is  accentuated,  especially  on  the  line 
of  rail  of  short  radius,  since  the  latter  receives  a  larger  part  of 

"Trains  are  run  left-handed  on  the  Paris,  Lyons  &  Mediterranean. 


DEFORMATION   OF  THE   TRACK.  65 

the  load  by  reason  of  the  inclination  calculated  for  the  highest 
speeds,  and  since  the  sliding  friction  of  the  tire  against  the  rail 
acts  in  the  direction  of  movement.  On  the  line  of  rail  of  long  radius 
the  movement  has  a  tendency,  on  the  contrary,  to  be  produced  in  an 
inverse  direction,  in  consequence  of  the  cutting  of  the  rail  by  the 
flange  of  the  engine.  This  effect  is  diminished  by  the  employment 
of  the  bogie  truck,  which  enters  the  curves  better.  On  a  right  aline- 
ment,  the  dragging  is  produced  most  thoroughly  on  the  outside  line 
of  rail,  in  consequence  of  the  unequal  subsidence  of  the  ties,  a  sub- 
sidence \vhich  consequently  produces  a  greater  loading  on  that  side 
of  the  track.  When  the  line  of  rail  of  the  short  radius  is  found  at 
the  same  time  on  the  outside,  the  two  movements  are  conjoined  and 
the  dragging  is  greater. 

The  ballast  acts  equally  either  for  increasing  or  diminishing 
the  importance  of  the  movement.  Mr.  Ferry  has  proved  an  advance 
of  %  in.  per  thousand  trains  on  track  laid  in  a  very  variable  ballast, 
that  is  to  say,  deprived  of  all  residue  by  sifting,  and  freshly  placed. 

But  the  explanation  given  by  Mr.  Coiiard  has  not  been  admitted 
by  all  the  technicists;  the  shock  which  is  produced  by  the  passage 
of  wheels  from  rail  to  rail  doubtless  has  an  influence,  since  the 
simple  substitution  of  angle  bars  for  fish-plates  has  diminished  the 
creeping,  but  it  ought  to  have  other  secondary  causes,  which  act  in 
the  same  direction,  and  which  complicate  the  study  of  the  phe- 
nomena. Thus  Professor  Johnson,  at  St.  Louis,  attributed  the  creep- 
ing of  rails  to  the  undulatory  movement  studied  above,  which  is 
produced  in  consequence  of  the  oscillation  of  the  supports. 

The  resistance,  which  the  friction  between  the  rail  and  the  tie 
opposes  to  the  return  of  the  points  of  rest  of  the  rail  on  its  sup- 
ports, gives  consequently  a  slow  creeping  of  the  rail  in  comparison 
with  the  ties. 

The  shock  and  the  undulatory  movement  exercise  a%ery  serious 
action  on  the  creeping;  they  are  not,  perhaps,  the  only  elements 
susceptible  of  producing  it.  It  has  been  seen,  in  fact,  that,  on  a 
line  of  two  tracks,  each  of  which  is  only  traversed  by  trains  going 
in  the  one  direction,  the  dragging  of  the  rail  is  more  sensible  on 
the  exterior  side,  that  is  to  say,  on  the  outside  space.  Mr.  Coiiard 
thought  that  this  fact  was.  due  to  the  unequal  subsidence  of  the  ties, 
which  tend  to  incline  to  the  side  where  the  ballast  and  roadbed 
present  the  least  resistance.  This  explanation  does  not  suffice,  since 
the  same  anomaly  is  observed  on  lines  with  four  tracks;  it  is  al- 
ways the  left  line  of  rail  in  the  direction  of  movement  which  is 
submitted  to  the  strongest  dragging  force.  Other  explanations  have 


«6  TRACK  DEFORMATIONS. 

been  sought,  such  as  the  lack  of  symmetry  of  the  engine,  which 
would  be  more  heavily  loaded  on  the  left,  the  position  of  Giffard, 
-etc.;  it  suffices  to  cite  them,  in  order  not  to  retain  any  of  them,  for 
they  do  not  rest  on  any  precise  observation. 

The  question  then  remains  intact,  and  has  not  been  entirely 
-solved,  in  spite  of  all  the  interest  which  it  presents;  but  it  is  neces- 
sary to  retain  the  influence  of  the  shock  and  of  the  undulatory  move- 
ment, whose  effect  is  of  great  importance,  especially  that  of  shock, 
.as  I  have  shown. 

The  author  will  endeavor  to  show,  in  the  second  part  of  this 
work,  the  methods  employed  for  combatting  the  creeping,  and  to 
indicate  those  which  should  be  adopted  to  arrive  at  a  better  result. 

REDUCTION     OF     THE    GAGE     OF     THE    TRACK    ON     TANGENT     AND    THE 
WIDENING  ON    CURVES. 

Mr.  Coiiard  has  pointed  out,  in  very  precise  experiments,  of 
which  he  has  given  an  account  in  the  Revue  des  Chemins  de  Fer  for 
July,  1888,  that  in  right  alinement  the  rails  are  inclined  to  the 
interior  of  the  track,  and  that  on  curved  alinement  the  same  move- 
ment takes  place  to  the  outside.  He  has  equally  proved  that  at  the 
joint  the  rail  in  advance  is  inclined  more  than  the  following  rail, 
and  that  the  wheel  falls  from  the  first  on  the  second. 

The  mean  inclination  on  right  alinement  is  as  follows:  With 
a  good  tamping  of  the  tie,  .067  in.  on  the  advance  rail,  and  .028  in. 
on  the  following  rail  (line  of  rail  on  the  outside). 

With  a  defective  tamping,  .08  in.  on  the  advance  rail  and  .04  in. 
on  the  following  rail  (line  of  rail  on  the  outside).  The  line  of  rail 
on  the  outside  should  incline  more  than  the  line  of  rail  of  the  inter- 
track  space.  The  consequence  of  the  unequal  inclination  of  the  two 
rails,  advance  and  following,  is  to  super-elevate  the  advance  rail 
in  companion  with  the  following  rail,  to  provoke  a  fall  of  the 
vehicle,  which  withdraws  considerable  length  of  the  following  rail 
from  contact  with  the  wheels,  and  which  increases  at  the  same  time 
as  the  inclination. 

Mr.  Coiiard  considers  that  this  inclination  would  produce  the 
same  effect  as  if  the  rail  were  pivoted  about  the  interior  edge  of 
its  base.  He  has  established  that  the  jerk  which  is  felt  at  the  pass- 
age of  joints  cannot  be  attributed  to  the  space  left  between  the 
two  rails  for  expansion,  but  to  the  unequal  level  produced  by  the 
unequal  rotation  of  the  two  extremities  of  the  rails.  "The  shock 
brings  about,  little  by  little,  the  unpacking  of  the  tie  at  the  follow- 
ing end  of  the  even-joint,  and  the  latter  circumstance  augments 


DEFORMATION  OF  THE   TRACK.  67 

still  more  the  jerking  at  the  passage  of  the  joint,  the  lowering  of 
the  following  tie  tending  to  increase  the  unequal  level  of  the  two* 
rails." 

On  a  curve,  the  first  axle  of  the  train  is  that  which  most  de- 
forms the  track.  The  line  of  rail  on  the  side  of  the  short  radius  is 
projected  towards  the  center  of  the  curve;  the  line  of  rail  on  the 
side  of  the  long  radius  is,  on  the  contrary,  inclined  to  the  interior 
of  the  track;  the  first  axle  only  produces  an  inclination  to  the 
exterior. 

Mr.  Coiiard  has  analyzed  intelligently  the  phenomena  of  nar- 
rowing and  widening  of  the  gage  of  the  track,  but  he  has  not  per- 
haps given  the  exact  reasons.  If  he  has  indeed  seen  that  the  widen- 
ing of  the  track  ought  to  be  attributed  to  an  exaggerated  super- 
elevation given  to  the  rail  of  long  radius  on  curves,  it  does  not  seem 
that  he  has  found  the  reason  for  the  reduction  of  the  gage  of  the 
track,  which  is  produced  on  tangents. 

I  have  shown,  by  numerous  experiments,  that  the  wood  tie  em- 
ployed on  railroads,  bends  in  a  very  perceptible  manner.  The  rail 
tends  then,  in  consequence  of  this  flexure,  to  be  inclined  towards 
the  interior  of  the  track,  and  this  effect  is  again  augmented  by  the 
compression  of  the  supports  and  their  deformation  on  the  interior 
side,  as  we  shall  see  further  along,  since  the  inclination  of  one-twen- 
tieth given  to  the  rail,  and  the  flexure  of  the  tie,  act  in  the  same 
direction,  and  bring  the  weight  of  the  load  towards  the  interior. 
The  unequal  inclination  of  the  two  rails  is  also  a  consequence  of 
the  flexure,  since  the  tie  at  the  advance  end  of  the  even  joint  under- 
goes the  maximum  flexure  and  draws  over  the  rail,  while  the  tie 
of  the  following  end  of  the  even  joint  has  not  yet  attained  its  com- 
plete deformation,  and  the  imperfect  splicing  does  not  induce  the 
two  rails  to  act  at  the  same  time. 

Besides,  Mr.  Coiiard  has  implicitly  recognized  the  causes  given 
above,  since  he  has  proved  that  the  placing  of  plates  under  the 
rails,  distributing  the  load  over  a  greater  surface,  diminishes  the 
effect  of  the  reduction  of  the  gage. 

COMPRESSION    OF    THE   TIES   RIGHT   AT   THE    SUPPORTS. 

The  rails  are  fixed  on  the  ties,  whether  it  be  directly  or  indi- 
rectly, by  means  of  plates  of  support;  in  the  first,  as  in  the  second 
case,  but  especially  in  the  first,  the  wood  is  compressed  excessively, 
and  finishes  by  taking  a  permanent  deformation. 

tu  the  bending  tests  of  ties  the  lowering  of  the  rail  has  been 
marked,  apart  from  the  points  taken  on  the  tie.  This  lowering, 


68  TRACK  DEFORMATIONS. 

which  has  always  been  found  in  excess  of  that  of  the  neighboring 
points,  gives  the  measure  of  the  sinking  of  the  rail  on  its  support, 
and,  consequently,  of  the  compression  of  the  wood.  In  order  to 
-appreciate  its  value,  mean  figures  of  the  lowering  of  the  points  of 
the  tie,  situated  on  each  side  of  the  rail,  have  been  taken,  and  the 
difference  between  these  figures  and  those  of  the  lowering  of  the  rail 
have  been  given.  The  table  on  the  following  page,  which  sums  up 
these  calculations,  brings  out  the  fact  that  the  sinking  of  the  rail  in 
its  support  is  about  twice  as  great  with  ordinary  ties  as  with  com- 
posite ties. 

It  is,  however,  necessary  to  remark  that  this  reduced  sinking 
is  not  due  entirely  to  the  reduced  compression  of  the  wood,  but  that, 
apart  from  this  fact,  it  is  also  necessary  to  take  account  of  the 
flexure  of  the  tie,  which  increases  the  compression  under  the  base 
at  the  inside  edge  of  the  rail,  already  greater  by  reason  of  the  incli- 
nation of  1  in  20.  But  this  flexure  increases  but  little  the  effect  of 
the  sinking,  for  the  slope  of  the  bent  tie  scarcely  reaches  1  in  400, 
a  negligible  quantity  in  comparison  with  the  inclination. 

Whatever  the  reason  may  be,  the  compression  of  the  wood  is 
produced,  and  it  is  a  maximum  on  the  interior  side,  because,  for 
the  reasons  given,  the  loads  are  carried  on  this  side.  This  coin- 
cides with  the  statement  of  Mr.  Coiiard,  set  forth  in  his  article  for 
July,  1888,  in  the  Revue  ties  Chemins  de  Per;  he  has  claimed  cor- 
rectly that  the  rail  turns  about  its  interior  edge,  which  produces 
a  super-elevation  of  the  advance  rail  in  comparison  with  the  follow- 
ing rail,  and  determines  a  drop  at  the  passage  of  the  joint. 

The  increases  of  the  resistance  of  ties  to  compression  presents 
very  great  interest,  and  is  intimately  connected  with  the  question 
which  now  occupies  us,  that  is  to  say,  the  attempt  to  find  out  how 
to  avoid  deformations,  in  order  to  obtain  a  better  circulation  of  traf- 
fic, and  realize  more  considerable  speeds.  After  the  passage  of 
trains,  the  rail  returns  to  its  primitive  position;  the  base  reacts 
on  the  head  of  the  screw  spike,  tending  to  tear  it  from  its  socket. 

PULLING  OUT   SCREW   SPIKES. 

The  sinking  of  the  rail  in  its  support,  the  least  bending  of  the 
tie,  and  the  elastic  reaction  which  results  from  it,  exercise,  slowly 
but  surely,  pulling  effects  on  the  screw  spikes.  At  the  end  of  a  cer- 
tain time,  the  screw  spikes,  which  unite  the  rail  with  the  ties,  no 
longer  hold,  especially  those  which  on  a  tangent  are  located  in  the 
interior  of  the  track.  They  can  be  readily  pulled  out  of  their  holes. 

That  is  why  a  study  of  the  fastenings  is  necessary;   it  is  neces- 


DEFORMATION   OF  THE  TRACK.  69 

COMPRESSION  OF  SUPPORTS  AND  INCLINATION  OF  RAIL. 

Figures  for  points  Diff.  bet.  the 

No.          observed  to  the  right  and  Mean  Figures  figures  of 

of  ties.      , left  of  the  rail x          figures.  for  the  rail.      cols.  4  and  5 

1.                       2.                  3.                          4.                          5.  6. 

1.    Wooden  Ties  (P.  M.  rails) — Line  of  long  radius. 

5  -14.5              20.0                       17.2                       18.0  0.8 

6  25.0              19.5                       22.2                       26.0  3.8 

7  15.0              21.0                       18.0                       20.5  2.5 
20                     13.0              19.0                       16.0                       17.5  1.5 

Mean  compression    2.1 

Line  of  Short  Radius. 

5  24.0              21.0                       22.5                       26.0  3.5 

6  22.0              23.5                       22.7                       26.0  3.3 

7  27.0              24.0                       25.5                       29.5  4.0 
20                     25.5              21.0                       23.2                       27.0  3.8 

Mean  compression    3.6 

2.    Composite  Ties   (P.  M.  rails) — Line  of  long  radius. 

7A                 23.0              22.5                       22.7                       23.5  0.8 

7B                  22.0              23.0                       22.5                       23.0  0.5 

9                     12.0              14.5                       13.2                       15.5  2.3 

10  19.5              19.5                       19.5                       21.0  1.5 

11  25.5  26.5  26.0 

12  11.0              12.0                       11.5                       13.3  1.8 
15                     12.0              14.5                       13.2                       13.5  0.3 

15  11.0              14.0                       12.5                       13.5  1.0 

16  9.5              10.5                       10.0                       10.5  0.5 

18  19.0            .19.5                       19.2                       19.5  0.3 

19  15.5              13.5                  •     13.5                       15.5  2.0 

Mean   compression    1.1 

Line  of  Short  Radius. 

7A  32.5  37.5  35.0  35.0 

7B                  33.0              33.0                       33.0                       36.5  3.5 

9                     19.5              16.0                       17.7                       23.0  5.3 

10  24.0              24.0                       24.0                       29.0  5.0 

11  23.5              24.0                       23.7                       27.5  3.8 

12  19.0              17.0                       18.0                       19.0  1.0 

13  21.0              22.0                       21.5                       27.5  6.0 

14  23.0              24.5                       23.7                       25.5  1.8 

15  17.0              19.5                       18.2                       21.0  2.8 

16  19.5              20.0                       19.7                       23.0  3.3 

17  15.0              14.0                       14.5                       16.r>  2.0 
"18                     23.5              26.0                       24.7                       26.0  1.3 

19                     20.0              20.0                       20.0                       21.0  1.0 

Mean  compression    2.8 

3.    Recapitulation. 

Wooden  ties — line  of  long  radius. 2.1       Wooden  ties — line  of  short  radius. 3.6 

<Comp.     ties — line  of  long  radius. .1.1       Comp.      ties — line  of  short  radius. 2.8 

Difference  in  favor  of  Comp.  tie.  1.0          Difference  in  favor  of  Comp.  tie. 0.8 
NOTE. — The  figures  are  expressed  in  tenths  of  millimeters. 


70 


TRACK  DEFORMATION. 


sary  to  know  the  limiting  force  which  can  be  applied  to  the  screw 
spikes  before  they  can  be  withdrawn,  and  that  which  they  can  sup- 
port before  a  spreading  of  the  track  .98  in.  takes  place,  considered 
as  sufficient  to  put  it  out  of  service;  finally,  the  limiting  force  which 
can  be  imposed  on  it  before  obtaining  excessive  turning. 

These  experiments  have  been  executed  with  two  very  ingenious 
pieces  of  apparatus  devised  by  Mr.  Albert  Collet,  and  which  he  has 


Fig.    13 — The   Extrahometre,   Vertical   Section    and    Front   View. 

named  the  extrahometre  and  the  declimetre.  They  have  been  used, 
as  will  be  seen  later,  on  ordinary  and  composite  ties,  with  or  with- 
out treenails,  of  which  Mr.  Collet  is  the  inventor. 

The  extrahometre  is  a  very  small  testing  apparatus,  with  register 
and  with  means  for  measurement,  weighing  only  13.23  Ibs.  and 
able  to  support  a  force  of  8.82  net  tons  which  is  exercised  vertically 
on  the  head  of  the  screw  spike,  in  the  manner  for  extracting.  This 
force  is  produced  up  to  the  moment  when  the  wood  is  torn  and 


DEFORMATION  OF  THE  TRACK.  71 

yields;  at  that  moment  there  is  no  more  resistance  in  consequence 
of  more  force. 

This  apparatus  (Fig.  13),  entirely  of  steel,  is  composed  of  a 
square  pedestal,  S,  serving  as  point  of  support,  through  the  opening; 
of  which  is  introduced  the  head  of  the  screw  spike,  which  is  en- 
gaged in  the  foot  of  the  dog,  G.  The  foot  of  the  dog  is  in  one  piece 
with  the  traction  cheeks,  F,  and  the  nut,  D,  in  which  travels  the 
motor  screw,  V,  directed  at  R,  by  the  key  for  screw  spikes.  Between 
the  two  cheeks  is  a  cylinder,  C,  whose  two  flanges,  N,  rest  on  the 
pedestal.  The  cylinder  .contains  liquid  glycerine  in  T,  and  above,. 
a  piston,  P,  packed  with  leather,  carrying  a  small  ball,  L. 

At  the  extremity  of  one  of  the  flanges,  N,  a  pressure  gage  re- 
ceives and  records  the  pressure  exercised  on  the  liquid  passing  by 
the  capillary  conduit,  M.  B  is  a  release  latch,  and  E  a  symmetrical 
arrangement  allowing  the  adoption  of  a  standard,  in  order  to  verify 
the  pressure  gage  in  case  of  necessity.  The  travel  of  the  foot  of 
the  dog  is  1.57  in.  This  apparatus  is  in  use  by  several  railroad  com- 
panies in  France. 

The  table  which  follows  gives  the  results  obtained  on  composite 
ties: 

COMPOSITE  CROSS  TIES. 

—Without  treenails s  .       , —        -  With  treenails  -       — , 

Forces  on  screw  spikes  Forces  on  screw  spikes 

)f  the —      — N  Raise 

Lateral  of  the  middle 

wedges.  wedges. 

3.     15,983  Ibs.  0  in.* 

3.  0  " 


,  of 

the  , 

Raise 

t  

Middle 

Lateral 

of  middle 

Midd 

wedges. 

wedges. 

wedges. 

wedg< 

13,228  Ibs. 



0.04  in. 

15,873 

12,235    "t 

0.02  " 

15,983 

12,787    " 

13,228  Ibs. 

0.0     "  t 

11,464    " 

11,574    " 

0.0     "  $ 

13,228    " 

13,007    " 

0.0     "  $ 

11,023    " 

12,787    " 

0.0     "  § 

Observations  : 

*Wooden  wedges  of  creosoted  oak,  but  split  by  frost. 
fThis  wedge  was  split  before  the  trial. 
JMean    force  : — Middle   wedge   without  treenail,    12,324   Ibs. ;     lateral   wedge, 

without  treenail,  12,654  Ibs. 
§Mean  force  on  the  two  wedges,  12,456  Ibs. 

The  following  table  gives  the  results  of  trials  on  wood  ties: 

„ Forces  on  the  screw  spikes » 

Nature  of  ties.  Without  treenails.     With  treenails. 

New  oak  ties,   creosoted    13,668.5. Ibs.  15,873.1  Ibs. 

Piece  of  new  good  spruce,  creosoted 7,936.5    "  11,023.0    " 

Apart  from  the  experiments  related  above,  and  which  were 
made  in  my  presence,  I  have  embodied  the  results  of  similar  experi- 
ments executed  by  the  employees  of  the  P.  L.  M.  Co.,  some  days 
before.  It  was  interesting  to  compare  the  results  obtained  with 


72  TRACK  DEFORMATION. 

a  more  complete  series,  in  which  the  wood  ties  tested  were  with  or 
without  treenails.  It  is  not  necessary  to  give  here  the  details  of 
these  experiments,  it  would  be,  in  fact,  going  beyond  the  outline 
of  the  study  which  we  have  undertaken,  but  it  is  fitting  to  remember 
that  the  resistance  to  withdrawal  of  the  screw  spikes  is  the  fol- 
lowing: 

1st.     In  pine  ties   Approximately     7,716  Ibs. 

2d.       In  pine  ties  with  treenails , .  11,023    " 

3d.      In  new  oak  ties 13,228    " 

4th.    In  new  oak  ties  with  treenails    "  15,432    " 

5th.    In  oak  ties  in  service  for  eight  years   7,496    " 

6th.    In  oak  ties  in  service  for  8  years,  new  treenails  "  12,125    " 

7th.    In  oak  ties  with  old  treenails   "  7,496    " 

The  limit  to  extraction  of  the  screw  spikes  in  the  composite 
cross  ties  is  raised  as  an  average  to  12,456  Ibs.,  that  is  to  say,  to 
A  figure  which  is  very  near  that  which  was  obtained  with  new  oak 
ities;  the  wood  of  the  wedges  was,  however,  of  bad  quality,  pre- 
senting a  good  many  fissures,  and  having  all  the  appearances  of 
ibeing  split  by  frost.  Their  own  resistance  was  certainly  inferior 
to  that  which  it  would  have  been  if  the  material  employed  had  been 
sound.  The  central  wedge  once  in  place,  no  longer  rises,  whatever 
may  be  the  pressure  to  which  the  screw  spike  is  submitted;  the 
fastening  is  then  secured  in  a  certain  fashion,  and  even  more  ef- 
ficiently than  it  is  generally,  by  reason  of  the  compression  of  the 
fibers  of  the  wood.  The  wedging,  or  rather  the  squeezing,  of  the 
pieces  of  wood,  which  one  would  consider  a  priori,  as  one  of  the 
weak  points  of  a  composite  cross  tie,  becomes,  on  the  contrary,  one 
of  its  principal  advantages;  it  seems  that  the  bringing  together  of 
the  fibers  of  the  wood  arising  from  the  squeezing,  gives  to  that 
material  a  resistance  superior  to  that  which  it  would  have  had  in 
a  free  state.  It  is  that  which  explains  also  the  reason  why  the 
employment  of  the  treenail  in  ties  gives  a  superior  resistance  to 
that  of  the  wood  which  constitutes  them;  the  treenail  has  not,  so 
to  speak,  any  resistance  of  its  own.  That  which  demonstrates  it, 
is  that  the  limit  of  extraction  varies  according  to  the  nature  of  the 
wood  which  envelops  it,  and  which  latter  is,  so  to  speak,  the  inter- 
mediary between  the  resistance  of  the  treenail  and  that  of  the  wood, 
which  surrounds  the  latter.  It  follows  that  this  resistance  ought 
to  hold  the  fibers  of  the  wood  envelope  in  compression  more  or 
less  great,  since  the  more  fibrous  and  elastic  the  wood  is,  the  more 
considerable  is  the  resistance. 

Thus  the  compression  of  the  wood  constitutes  one  of  the  prin- 
cipal merits  of  the  tie,  and  in  order  to  exhibit  it,  I  have  provided 
the  wedges  with  treenails.  The  result  has  been  what  was  expected; 


DEFORMATION  OF  THE  TRACK. 


73 


the  compressed  horizontal  fiber  of  the  blocks  reacted  on  the  ver- 
tical fiber  of  the  treenail,  and  the  resistance  was  increased  by  about 
20  per  cent,  that  is  to  say,  that  with  blocks  composed  of  sound 
wood,  fibrous  and  elastic,  and  with  treenails  introduced  at  the  point 
where  the  fastenings  are  placed,  a  resistance  was  obtained  which 
surpassed  known  limits.  It  was  interesting,  consequently,  to  make 
new  experiments  with  that  idea,  and  to  see  how  cross  ties,  com- 
posed of  wooden  blocks  of  the  kind  indicated  above,  would  behave. 
For  that  effect,  cross  ties  provided  with  wooden  blocks  of  horn- 
beam and  elm  were  experimented  with  like  the  preceding,  but  un- 
fortunately, the  woods  employed  were  absolutely  baked,  and  the 
trials  offered  no  more  than  a  relative  interest. 

In  spite  of  these  very  disadvantageous  conditions,  the  results 
have  nevertheless  been  very  satisfactory,  since  there  was  obtained 
on  a  middle  wedge  a  force  of  19,621  Ibs.  (limit  of  power  of  the 
extrahometre) ,  and  on  the  lateral  wedges  forces  varying  between 
15,432  Ibs.  and  16,094  Ibs.  The  results  of  this  last  experiment  are 
set  down  in  the  following  table: 

COMPOSITE  TIES. 
Forces  on  the  screw  spikes 

-x        Raise 

Observations. 


Mean  force  on  a  lateral  wedge,  15,- 
300  Ibs. 

These  blocks  were  prepared  specially 
for  the  tests ;  they  were  not  creo- 
soted,  because  they  were  not  to 
be  used  in  the  tracks ;  they  were 
in  full  process  of  decomposition, 
as  we  have  been  able  to  account 
for  it  to  ourselves,  having  broken 
several  of  them. 

2<Z.    Elm  wedges. 

Wood  as  above. 


,  —of  the  v 

sedges  -^        Raise 

On  the  sides      of  midd 

In  the  middle. 

(lateral.)          wedges 

1st     Horn-b< 

14,330  Ibs. 

15.432  Ibs.            

17,637    " 

16,094    "              

14,110    " 

15,432    "               

12,346    " 

14,992    "               

14,110    " 

15,983    " 

14,330    "               

15.983    " 

12,676  Ibs. 
13,779    " 
11,023    " 
10,472    " 


13,669  Ibs. 

12,676  "  

13,448  "  

13,228  "  

11,684  "  

' 13,007  "  

11,905  "  

12,566  "  

The  object  of  the  experiments  with  the  dvclimetre  was  to 
measure  the  bending  of  the  tie  and  to  bring  about  the  overturning 
of  the  fastenings  under  increasing  forces,  having  as  an  effect  the 
spreading  of  the  track  to  the  limit  (.98  in.),  where  it  is  considered 
as  out  of  service. 


74 


TRACK  DEFORMATION. 


This  apparatus  is  essentially  composed  of  a  screw  and  nut,  and 
rests  on  the  heads  of  the  two  rails,  under  conditions  similar  to 
those  of  the  wheel  tires.  The  screw  acts,  through  the  intermediary 
of  a  ball  and  piston,  on  glycerine,  which  is  contained  in  a  reservoir, 
the  pressure  of  which  is  registered  by  a  pressure  gage;  it  tends 
to  spread  the  two  rails,  and  the  force  causes  the  tie  to  assume  a 
convex  curvature.  (See  Fig.  14.)  The  displacement  of  the  rail 
is  registered  and  amplified  by  an  independent  instrument. 


Fig.    14 — Declimetre;    Longitudinal   Section,    Plan    and    Elevation. 

This  apparatus  serves  also  to  measure  the  resistance  of  the 
track  to  lateral  displacement,  by  supporting  it  against  an  abutment 
pier,  and  by  acting  on  a  single  rail. 

The  experiments  were  made  on  composite  and  wood  ties,  at 
first  in  separate  units,  then  by  groups  of  two,  each  distant  from 
the  other  (13.78  in.).  The  ties  were  placed  on  two  supports,  nearly 
of  the  length  corresponding  to  that  of  the  tamped  bed.  Steel  ties 
in  use  on  the  state  system  were  also  experimented  with,  under 
similar  conditions. 


DEFORMATION  OF  THE  TRACK.  75 

The  apparatus  was  fixed,  in  the  first  case,  in  the  axis  of  the 
tie  to  be  tried,  and  in  the  second  case,  in  the  center  of  the  two 
ties.  In  order  to  measure  the  curvature  of  the  pieces,  which  it 
tended  to  produce,  and  which  made  known,  so  to  speak,  the  degree 
.of  their  rigidity,  there  was  opportunity  for  estimating  the  import- 
ance of  the  flexures  from  their  initial  position  which  these  pieces 
underwent.  To  this  effect  a  right  line  was  traced  on  the  ties,  whose 
two  extreme  points  were  placed  near  the  ends  of  each  of  the  pieces, 
.and,  at  a  given  moment,  the  flexure  in  comparison  with  this  line, 
now  become  curved,  was  measured,  by  describing  with  the  same 
points  a  new  right  line,  and  by  observing  the  departure  of  these 
two  lines  at  the  middle  of  their  length. 

This  apparatus,  which  tended  to  spread  the  two  sections  of 
rail,  acted  at  first  on  the  tie,  to  induce  its  flexure;  then,  when  this 


CT 


Not  reinforced.  Reinforced  at  ends. 

Fig.  15 — Ordinary  P.  M.  Tie  Plate. 

had  attained,  a  certain  degree,  which  corresponded  to  the  bending 
of  the  head  of  the  screw  spike  on  the  plate,  apart  from  its  shoulder, 
the  fastenings,  principally  those  placed  in  the  interior,  commenced 
to  be  overturned,  up  to  the  moment  when  the  base  of  rail  escaped 
from  the  head  of  either  of  the  interior  screw  spikes.  (Fig.  15.) 
This  effect  was  obtained  without  increase  of  force. 

These  experiments  have  shown  that  there  was  reason  for  con- 
solidating the  interior  fastenings,  and  for  increasing  the  number 
in  comparison  with  the  exterior  fastenings.  The  good  effect  of  the 
reinforcement  of  the  plates  in  use  on  the  P.  L.  M.  system  was  also 
proved.  In  the  type  employed,  the  head  of  the  screw  is  only  par- 
tially sustained  by  the  shoulder;  it  has  then  a  tendency  to  over- 
turn in  the  empty  space  until  it  meets  the  exterior  part  lying  below 
the  shoulder.  There  results  a  weakening  of  the  fastening  and  a 
.bedding  of  the  screw  spike  which  diminishes  the  resistance  to  this 


76 


TRACK  DEFORMATION. 


kind  of  force.  The  rail  is  no  longer  maintained  by  the  screw  spike, 
and  generally  escapes  from  the  fastening.  In  order  to  remedy  this 
disadvantage,  it  is  sufficient  to  prolong  the  shoulder  of  the  plate 
on  the  exterior.  In  the  trials  which  followed,  the  interior  screw 
spike  took  the  position  indicated  in  Fig.  15,  and  the  resistance  to 
overturning  was  increased  by  20  per  cent. 

The  experiments  with  the  declimetre  were  carried  on  in  like 
manner  with  the  steel  ties  of  the  State  System.  The  rails  were 
fixed  on  the  ties  through  the  intermediary  of  steel  plates,  with  an 
inclination  of  1  in  20,  and  bolted  on  their  upper  surface.  Three 
bolts  per  rail  were  used  in  the  first  test,  two  on  the  exterior  and 
one  in  the  interior;  in  the  second,  two  in  the  interior  and  one 
on  the  exterior.  The  declimetre  was  placed,  as  in  the  preceding 
experiments,  in  the  axis  of  the  tie.  The  forces  were  successively 
exercised,  and  were  noted  for  each  spread  of  the  rails  of  .2  in. 


Fig.  16 — Tie  Plates  Used  on  Wood  (Left)  and  Composite  (Right) 

Ties. 

up  to  .98  in.,  where  the  track  is  considered  out  of  service.  The 
deformations  of  the  beam,  placed  on  two  supports  right  at  the  rails, 
were  read  in  comparison  with  the  lower  and  horizontal  edge  of 
a  steel  rule,  resting  on  invariable  supports  parallel  with  the  tie. 
The  latter  was  raised  at  the  center  in  comparison  with  its  original 
position,  and  lowered  at  its  extremities;  the  curve  of  deformation 
was  thus  convex  upward.  «, 

It  would  take  too  long  and  be  without  great  interest  to  give 
the  detail  of  all  these  experiments.  They  are  summarized  in  the 
table  on  the  following  page. 

This  table  shows:  (1)  that  the  forces  were  proportional  to  the 
number  of  interior  fastenings;  (2)  that  the  forces  sustained  by 
the  composite  ties,  provided  with  ordinary  plates,  were  a  little  supe- 
rior to  those  undergone  by  the  wood  ties,  but  that  the  inverse  result 
was  obtained  in  the  experiments  with  reinforced  plates.  This  fact 


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78  TRACK  DEFORMATION. 

can  only  be  explained  by  the  more  complete  reinforcement  of  the 
shoulder  of  the  plates  employed  on  the  wood  ties.  In  fact,  for 
these  latter  pieces,  the  shoulder  was  prolonged  in  an  inclined  plane, 
C  D,  by  adding  a  piece  A  B  C  D  (Fig.  16),  while  we  were  satis- 
fied, for  the  plates  intended  for  composite  ties,  with  a  plane  G  H 
(Fig.  16),  much  less  inclined;  thus  the  heads  of  the  screw  spikes 
were  found  to  be  more  supported  on  the  first  plates  (Fig.  18), 
than  on  the  second  (Fig.  16),  which  explains  the  difference  in  the 
increase  of  the  forces. 

It  may  therefore  be  concluded  that  with  plates  absolutely  iden- 
tical, the  forces  would  have  increased  in  the  two  cases  in  the  same 
proportion.  Whatever  it  may  be,  no  track  is  submitted  in  practice 
to  the  forces  which  were  obtained,  and  these  latter  can  always  be 
considered  as  maxima,  which  will  never  be  reached. 


CHAPTER  V. 


DEFORMATION  OF  TIES. 

The  curves  of  deformation  of  these  different  ties,  a  deformation 
which  was  obtained  by  spreading  the  track,  acting  horizontally  on 
the  rails,  are  those  which  give  the  application  of  the  theory,  and 
the  theoretical  flexures  <are  very  close  to  those  which  were  observed. 

The  moment  of  the  flexure  to  which  the  wood  and  steel  cross 
ties  are  submitted  is  constant  for  all  sections;  the  curve  of  deforma- 
tion, determined  by  the  condition  that  the  beam,  resting  on  two 
supports  right  at  the  rails,  is  horizontal  at  the  middle  of  the  span, 
Js  then  represented  by  the  equation: 

Kx2  K   (la) 

E  1  y  = — — , 

2  2 

in  which  K  represents  the  moment  of  constant  flexure,  I  the  half 
span  of  the  beam,  a  the  length  between  the  extremity  of  the  beam 
and  the  raiK  by  taking  as  the  origin  of  co-ordinates  the  middle 
of  the  beam,  and  as  axes  the.  neutral  line  and  the  perpendicular 
•erected  at  its  middle. 

It  has  been  deduced  from  it  that  the  total  bending  of  the  beam, 
which  is  equal  to  the  sum  of  the  flexures,  at  the  middle  and  at  its 
-extremities,  is  given  by  the  expression: 


The  table  following  permits  a  comparison  of  the  observed  and 
theoretical  flexures,  calculated  as  has  just  been  described;  the  flex- 
ures obtained  have  been  taken  by  attaching  the  rails  to  the  cross 
ties  with  the  screw  spikes  in  the  interior,  which  assures  the  greatest 


80 


TRACK  DEFORMATION. 


solidity  to  the  fastening,  and  an  integral  transmission  of  the  force 
to  the  beam: 


Value 
of  the  force. 
2,205  Ibs  
4  409    "    . 

Bending 
,  of  1 
Wooden. 
180 
360 

moment 
;ie  v 
Steel. 

*  —  Wooden  ties  N 
Theoret- 
Observed.      ical. 

,  Steel 
Observed 

ties  ^ 
Theoret- 
.      ical. 

323 
605 

0.40  in. 

0.24  in. 

'5  291    " 

432 

0.26  in. 

0.29  in. 

8  818    " 

720 

0.64  in. 

0.47  in. 

9  9°0    " 

810 

0.44  in. 

0.55  in. 

11  023    "    

900 

0.80  in. 

0.59  in. 

13  228    " 

1.080 

834 

995 
1.116 

0.78  in. 

0.71  in. 

13  669    " 

1  116 

0.59  in. 

0.76  in. 

15,432    "    
16  259    "    

1.260 
1  328 

0.75  in. 
0.82  in. 

0.83  in. 
0.88  in. 

16  314    "        .    . 

.    .        1  332 

0.69  in. 
0.91  in. 

0.91  in. 
1.03  in. 

18.298    "    . 

1.494 

Two  observations  may  be  made  on  the  results  set  down  in  this 
table: 

1.  The  theoretical  flexures  of  the  wood  tie  are  sensibly  equal 
to  the  flexures  observed  within  the  limits  of  elasticity  of  the  wood, 
that  is  to  say,  in  the  case  in  question,  up  to  a  force  of  11,023  Ibs., 
corresponding  to  a  bending  of  .79  in.     When  this  bending  is  reached, 
it  is  remarked  that,  under  increasing  forces,  the  bending  diminishes, 
which  corresponds  to  a  new  state  of  the  body,  which  takes  a  perma- 
nent deformation,  and  is  extended  while  taking  a  less  curvature. 
Besides,  from  this  moment,  the  wood  becomes  brittle,   and  several 
ties   were   broken   under   the  plate,   where   the   weakest  section   is 
found  by  reason  of  the  adzing  for  the  plate. 

2.  The  theoretical  flexures  of  the  steel  tie  are  a  little  superior 
to  those  which  were  observed.     The  reason  for  it  is  the  following: 
The  plates  of  support  for  the  rail  were  riveted  to  the  upper  sur- 
face of  the  cross  tie  and  became  a  part  of  it.     An  increase  of  sec- 
tion  results,   for  a  notable  length  of  the   beam    (about  23.62   in.), 
and,  consequently,  of  the  moment  of  inertia;    the  latter,   which  in 
the  normal  section  is  only  168,  is  increased  by  the  moment  of  the 
plate,  that  is  to  say  256,  a  value  which  reaches  nearly  double  the 
inertia  of  the  section  of  the  ties. 

The  latter  has,  then,  from  this  fact,  an  exceptional  rigidity, 
which  explains  the  difference  observed  between  the  theoretical  and 
recorded  flexures. 


DEFORMATION  OF  TIES.  81 

STRESS    OF    METAL  AND    OF    WOOD. 

It  is  possible,  after  having  studied  the  deformation  of  cross 
ties,  to  investigate  the  stress  of  metal  and  wood  resulting  from  this 
deformation.  It  is  given  by  the  formula: 

x  z 


R  = 


I 
in  which  R  is  the  stress  per  unit  of  surface,  x  the  bending  moment, 

—^  the  resisting  moment  of  the  beam. 

The   table   which    follows   gives   for   each   force   the   maximum 
stress  to  which  the  extreme  fiber  of  the  sections  is  submitted. 


, Moment —  — — >  Value  of  force,  in 

Value                       , Bending ,  ¥ Resisting N    , Ibs.  per  sq.in. » 

of  force.  Wood  tie. Steel  tie.  Wood  tie.  Steel  tie.  Wood  tie.     Steel  tie. 

2,205  Ibs 180         135  18  30  353  6,400 

4,409     "    360         270  .  .  .  .  711  12;80() 

5,291     "    432         323  .  .  .  .  853  15,645 

8,818    "    720         540  ..  ..  1,422  

9,920    "    820         605  ..  ..  ..T  28,589 

11,023    "    900         675  ..  ..  1,778  

13,228    "    1.080         810  ..  ..  2,133  

13,669    "    1.116         833  ..  ..             39,498 

15,432    "    1.260         945  .  .  .  .  2,489 

16,259    " 1.328       992  ..  ..  2,617  

16,314    "    1.332         995  ..  ..              47,164 

18,298    "    1.494     1.116  52,910 

It  is  observed:  1.  That  the  wood  tie  was  stressed,  in  the  ex- 
periments accomplished,  very  near  to  the  limit  of  elasticity  of  the 
material  which  composes  it,  since  the  latter  is  nearly  2,133  Ibs. 
per  sq.  in.,  as  was  established  in  the  study  of  the  deformation.  The 
result  to  be  drawn  is  that  a  wood  cross  tie  ought  never  to  take  a 
flexure  greater  than  0.40  in.  under  penalty  of  being  exposed  to 
rupture. 

2.  That  the  steel  tie  was  stressed  to  a  limit  near  that  of  rup- 
ture, 52,626  Ibs.,  in  place  of  64,004  Ibs.  per  sq.  in.,  and  that  it  has 
a  resisting  moment  little  higher,  since,  under  a  feeble  force  its 
stress  reaches  the  limit  generally  admitted,  6,400  Ibs.  per  sq.  in.; 
it  is  true  that  the  plate  or  the  chair  can  reduce  in  a  large  measure 
the  calculated  stress. 

CURVE  OF  DEFORMATION   OF  THE  COMPOSITE  TIE. 

The  composite  tie  can  be  considered  as  an  armored  beam,  com- 
posed of  a  steel  envelope  and  of  a  wooden  furring;  the  union  be- 
tween these  elements  is  so  intimate,  in  consequence  of  the  squeez- 
ing of  the  pieces,  that  these  two  elements  may  be  considered  to  form 
an  indivisible  whole,  the  one  coming  to  aid  the  other,  to  resist  the 


.82 


TRACK  DEFORMATION. 


0.2O 


forces  to  which  they  are  submitted  as  a  whole.     Such  a  solid  may, 
therefore,  well  be  compared  to  a  beam  of  armored  cement,  in  which 
the  elements  are   associated   in   a   manner   so   intimate,   that   each 
takes,  within  the  limits 
of  its  elasticity,  the  part 
of   the    force    which    it 
can  bear. 

The  experiments 
which  were  made  on 
the  sliding  of  the 
wedges,  or  the  single 
wedge  in  the  interior  of 
the  metallic  body,  have 
shown  the  good  founda- 
tion for  this  conception. 


SECTION  OF  COMPOSITE  TIE. 


For  these  tests,  rails,  tie  plates,  and  screw 
spikes  were  removed,,  leaving  the  wedges  and 
blocks  entirely  free  to  slide  in  their  envelope. 


The   tie    was   butted   at 
one    of    its    extremities 

against  a  wall,  or  against  a  very  solid  obstacle;  the  declimetre 
exercised  its  force  against  the  other  extremity  (Fig.  17). 
The  force  which  was  thus  exercised  was  raised  to  15,432  Ibs. 
before  sliding  began.  This  force  is  much  greater  than  that  which 
is  necessary  for  bedding  the  fastenings,  since  a  force  of  1,543  Ibs. 
suffices  for  overturning  the  head  of  the  screw  spike  on  the  plate, 
which  was  displaced  0.4  in.;  for  a  displacement  0.6  in.  the  force 
was  raised  to  5,732  Ibs.  It  can  be  concluded  from  this  that  the 
fastenings  will  yield  before  either  of  the  blocks  has  commenced  to 
slide,  and  that  the  plate  will  never  injure  the  flanges  of  the  skele- 
ton which  surrounds  it. 

Each  of  the  blocks  thus  forms  with  the  metallic  skeleton,  a  solid 
whole,  which  permits  of  calculating  with  exactness  the  forces 
which  are  developed  in  each  of  the  parts  of  the  system. 

Three  sections  must  be  considered:  the  first,  where  the  furring 
and  the  envelope  are  complete;  the  second  where  the  envelope  is 
defective  in  its  upper  part,  that  is  to  say  right  at  the  fastenings; 
the  third  where  the  envelope  exists  alone,  without  furring,  which 
-occurs  at  the  extremities  and  in  the  central  part  of  the  piece. 


*•! 


»    « 

§! 


I 

O 

O 


01 

-D 

V 


CD 


84 


TRACK  DEFORMATION. 


The  table  which  follows  gives,  comparatively,  the  observed  and 
the  theoretical  flexures  calculated  by  graphical  statistics  (Fig.  18) : 


Value 


-Bending  moment.- 


-Flexures.- 


of  force.  1st  Sec.  2d  Sec.  3d  Sec.  Observed.  Theoretical. 

4,409  Ibs.  337  377  325  0.12  in.  0.10  in. 

8,818  "  674  754  649  0.16  "  0.20  " 

11,023  "  843  942  812  0.21  "  0.25  " 

13,228  "  1.011  1.130  974  0.23  "  0.30  " 

15,432  "  1.180  1.319  1.137  0.28  "  0.34  " 

16,314  "  1.248  1.394  1.201  0.28  "  0.36  " 


Q/S 


O.ZS 


O.2O 


0,25 


O.4O 


Fig.    18 — Graphic    Representation    of   the    Bending    of    Composite 
Tie  (Wood  and  Steel). 


Amount  of 

force. 
2,205  Ibs. 
4,409    " 

8,818    " 
11,023    " 


Theoretical 
bending. 

0.05  in. 
.10   "    . 
.20  " 


Amount  of 
force. 

13.228  Ibs. 
15.432    " 
16.314    " 


Theoretical 

bending. 

0.30  in. 

.34   " 

.36  " 


DEFORMATION  OF  TIES.  85 

The  theoretical  flexures  approach  closely  to  the  observed  flex- 
ures; a  little  smaller  under  the  initial  forces,  they  surpass  the  re- 
sults of  observations  by  some  millimeters,  when  the  forces  are 
increasing.  It  seems  that  the  rigidity  goes  on  increasing  at  the 
same  time  as  the  latter,  in  consequence  of  the  still  more  intimate 
connection  of  the  materials.  This  rigidity  is  apparent,  for  they 
are  the  supports  which  react  and  reduce  the  flexure. 

Whatever  it  may  be,  this  study  proves  that  the  theoretical  bend- 
ing of  the  composite  tie  is  about  three  times  less  than  that  of  the 
wood  tie  and  of  the  steel  tie,  when  these  pieces  are  submitted  to 
horizontal  forces  of  4,409  Ibs.,  but  that  this  superiority  diminishes 
when  the  forces  reach  15,432  Ibs.  (Bending  of  the  composite  cross 
tie  about  two  times  less.) 

If  one  considers  the  composite  tie  as  an  armored  beam,  in 
which  each  of  the  elements  is  stressed,  while  taking  the  same  elon- 
gation, proportionately  to  its  coefficient  of  elasticity,  one  arrives 
at  the  following  result  for  the  three  sections  considered: 

Value  of  force,  Ibs 4,409  8,818  11,023  13,228  15,432  16,314 

Bending  moment :  1st  section 337  674        843  1.011  1.180  1.248 

2d         "      377  754         942  1.130  1.319  1.394 

3d         "      325  649         812  974  1.137  1.201 

Resisting  moment,  cu.  cm.  : 

1st   section — armored  part 1.764  

2d          "     — notched  part 1.066  

3d          "     — center  &  extrmty 1.217  

Value  of  force : 

1st  Sec.— Wood,  Ibs.  per  sq.  in.  270        541        669        811  939  996 

1st     "  — Steel,  "  "  "  5,405  10,810   13,370   16,214  18,775  19,912 

2d       "  —Wood,  "  "  "  498         996     1,237     1,493  1,735  1,835 

2d      "  —Steel,  "  "  "  9,956  19,912  24,748  29,869  34,705  36,710 

3d      "  —Wood,  "  "  "  

2d      "  —Steel,  "  "  "  7,567  15,133  18,917  22,700  26,484  27,991 

In  order  to  obtain  the  forces  to  which  the  elements  of  the 
composite  tie  are  submitted,  it  was  assumed  that  it  was  composed 
of  a  single  material  (wood  for  example),  and  the  moment  of  inertia 
of  the  steel  was  augmented  from  this  fact  in  the  ratio  of  the  co- 
efficients of  elasticity,  that  is  to  say,  of  20  to  1.  It  has  thus  been 
possible  to  calculate  the  position  of  the  neutral  axis  of  the  beam, 
supposedly  homogeneous,  and  to  deduce  from  it  the  stress  of  each 
of  the  elements,  that  of  the  steel  being  20  times  superior  to  the 
stress  of  the  wood. 

If  the  results  set  down  in  the  table  above  are  examined,  and 
if  they  are  compared  with  those  which  correspond  to  the  wood  and 
steel  ties,  it  is  observed  that  the  stress  of  the  material  is  much  less 
in  all  the  sections  of  the  first  than  in  the  two  others. 


86  TRACK  DEFORMATION. 

In  the  mortised  part,  the  material  is  still  stressed  within  an 
acceptable  limit,  9,956  Ibs.  per  sq.  in.,  under  a  force  very  much 
superior  to  that  to  which  it  can  ordinarily  be  submitted,  but  that 
part  is  quite  short,  and  is  reinforced  by  the  plate,  which  compen- 
sates, and  more,  for  the  metal  cut  away  for  the  placing  of  the  fast- 
enings. It  is  not  the  same  for  the  steel  tie  of  the  State,  which  is 
too  weak  in  each  of  its  sections,  except  right  at  the  fastenings, 
where  it  is  equally  reinforced  by  the  plate  or  chair.  Therefore,  it 
may  be  said,  that  the  composite  tie  tested  presents  two  sections  a 
little  less  resistant  reinforced  by  the  plates,  while  the  tie  of  the. 
State  is  weak  over  its  whole  length,  except  right  at  the  fastenings. 
The  two  situations  are,  then,  inverse  with  one  another,  and  all  to 
the  advantage  of  the  composite  tie. 

It  is  the  same  in  the  case  of  the  wood  tie,  which  is  weak 
everywhere,  and  which  has  not  a  great  rigidity,  since  it  takes  a 
flexure  very  much  superior  to  that  of  the  composite  tie.  In  order 
that  it  may  present  the  same  stiffness,  it  would  be  necessary  to- 
increase  the  moment  of  inertia,  which  ought  to  be  three  times 
higher  than  that  which  is  actually  possessed,  that  is  to  say,  that 
the  latter  should  attain  about  O  m  00015  in  place  of  O  m  00005. 
Supposing  that  the  depth  of  5.5  in.  is  maintained,  which  could  not 
however  be  increased  without  difficulty,  since  it  would  be  neces- 
sary at  the  same  time  to  place  a  greater  quantity  of  ballast  above 
the  tie,  it  ought  to  be  given  a  width  of  25.6  in.,  which  is  certainly 
inadmissible,  for  the  actual  base  would  be  tripled.  It  is  true  that 
the  same  result  can  be  obtained  with  ties  7.09  in.  deep,  11.8  in.  wide, 
but  we  believe  that  such  ties  would  not  be  easily  found,  at  least 
for  the  price,  which  would  render  their  use  impossible. 


CHAPTER  VI. 

STRESS   OF   TIES   IN   THE   TRACK. 

The  experiments  on  overturning,  joined  to  those  which  have 
been  related  above  on  flexure,  permit  the  determination,  with  a 
certain  exactness,  of  the  stress  of  the  material  composing  the  ties, 
under  the  effect  of  rolling  loads. 

In  tact,  it  has  been  seen  that  the  stress  of  the  wood  ties  was 
711  Ibs.  per  sq.  in.  for  a  theoretical  bending  of  0.24  in.;  for  a  mean 
bending  of  0.10  in.  observed  on  the  cross  ties  with  P.L.M.-A.  rails, 
the  stress  will  be  about  299  Ibs.  per  sq.  in.,  that  is  to  say,  that  these 
pieces  are  stressed  about  to  the  tenth  of  their  resistance  within  the 
limit  of  elasticity. 

As  regards  the  ties  with  P.M.  rails,  the  stress  is  142  Ibs.  per 
sq.  in. 

The  steel  tie  has  a  flexure  of  0.10  in.,  which  corresponds  to  a 
stress  of  about  5,405  Ibs.  per  sq.  in.  (about  one  eighth  of  the  elastic 
limit). 

The  elements  of  the  composite  tie  are  submitted  to  the  follow- 
ing forces  for  a  maximum  bending  of  0.012- in.: 

1st  section.        2d  section.         3d  section. 
Wood,  Its.  per  sq.  in..  .  27  50 

Steel,  Ibs.  per  sq.   in. .  .          540  996  754 

The  stress  is  thus  for  the  steel,  as  for  the  wood,  very  much 
inferior  to  the  admitted  resistances,  which  would  permit  of  re- 
ducing, from  that  point  of  view,  the  dimensions  of  the  materials 
employed. 

Space  does  not  permit  of  discussion  of  stresses  under  moving 
loads,  since  these  are  notably  inferior,  as  we  have  shown. 

Apart  from  the  forces  of  extraction,  and  overturning,  which 
are  the  most  important,  the  screw  spikes  are  exposed  to  excessive 
turning  in  their  sockets,  which  reduces  the  pressure  of  the  rail 
against  its  support.  This  disadvantage  is  produced  above  all  at  the 
moment  of  placing  the  screw  spikes,  and  when  they  are  retightened, 
the  trackman  can,  if  he  does  not  give  proper  attention,  exceed  the 
force  necessary,  and  render  useless  the  work  which  he  does. 


88 


TRACK  DEFORMATIONS. 


The  following  limits  are  admitted  as  the  force  determining  the 
excessive  turning  of  screw  spikes: 

Pine,  without  treenail   132  Ibs. 

Pine,  with  treenail    176    " 

Hard  wood,  oak  or  beech,  without  treenail 220    " 

Hard  wood,  oak  or  beech,  with  treenail 242    " 

The  force  is  observed  on  a  register  which  is  attached  to  an 
apparatus  invented  by  Mr.  Collet,  under  the  name  of  torsion  meter, 
and  which  is  placed  on  the  head  of  the  wrench  for  the  screw  spikes. 

The  company  placed,  about  three  and  one-half  years  ago,  1,056 
creosoted  pine  ties,  provided  with  Collet  treenails,  on  the  line  from 
Bourg  to  Chalon-sur-Saone.  In  the  course  of  the  month  of  August, 
1902,  after  a  traffic  of  about  13,500  trains,  some  trials  were  made 
with  the  torsion  meter,  in  order  to  learn  the  resistance  of  No.  6 
screw  spikes  against  excessive  turning. 

The  force  necessary  to  obtain  this  effect  on  the  screw  spikes 
set  in  the  treenails  of  the  original  placing,  was  159  Ibs.;  it  was  156 
Ibs.,  that  is  to  say,  sensibly  equal,  on  screw  spikes  placed  in  new 
treenails,  which  were  screwed  into  new  holes,  alongside  of  the  tree- 
nails of  the  original  placing,  in  the  middle  and  at  the  extremities 
of  the  cross  ties  in  service. 

It  is  well  to  remark  that  while  the  resistance  to  excessive  turn- 
ing does  not  seem  to  be  modified  with  time,  that  which  the  screw 
spike  offers  against  extraction  from  a  treenail  appears  to  diminish. 
It  is  a  fact  which  has  been  proved  by  Mr.  Ferry,  and  of  which  we 
will  seek  the  explanation  further  along. 

Whatever  it  may  be,  it  was  desired  to  give  an  account  of  the 
resistance  to  excessive  turning  in  composite  cross  ties,  compared 
with  ordinary  cross  ties  of  oak  or  pine  creosoted.  The  results  of 
these  trials  are  condensed  in  the  table  below: 


Kind  of  tie. 

Composite    ties — Lateral    wedge    of 
horn-beam  without   treenail.. 


Composite  ties — Lateral    wedge    of 
oak   without  treenail 


New  ties  of  creosoted  oak  : 

Without  treenail   

With   treenail    


New  ties  of  creosoted  spruce  : 

Without  treenail    

With  treenail.    . 


Limit 
of  forces. 


231  Ibs. 


231 


220 


242 


Remarks. 

No  excessive  turning  ;  at  231 
Ibs.  the  screw  spike  broke. 

No  excessive  turning ;  this 
force  could  not  be  exceed- 
ed by  2  men. 


Excessive    turning. 
No  excessive  turning. 


Excessive  turning. 
Excessive  turning. 


STRESS  OF  TIES   IN  THE   TRACK.  89 

These  trials  have  shown  that  the  resistance  to  excessive  turn- 
ing, for  screw  spikes  placed  in  the  blocks  of  the  composite  tie,  that 
is  to  say,  squeezed  by  the  play  of  the  skeleton  and  the  cross  bars, 
was  at  least  equal  to  that  of  screw  spikes  placed  in  ties  provided 
with  treenails.  The  same  cause  ought  to  produce  the  same  effects: 
the  squeezing  of  the  fibers  of  the  wood,  whether  by  the  treenails  or 
by  the  pressure  exercised  by  the  envelope,  sensibly  increases  the  re- 
sistance to  excessive  turning. 

The  good  hold  of  the  fastenings  presents  considerable  interest; 
for,  without  an  energetic  tightening,  the  rail  vibrates  on  its  support, 
the  track  becomes  jolty,  and  is  deformed  vertically,  since  it  is  no 
longer  sustained.  The  tie  is  hammered,  is  raised  up,  and  is  buried 
by  blows,  which  disorganize  the  ballast.  This  repeated  movement, 
joined  with  the  flexure  of  the  tie  and  with  the  compression  of  the 
wood,  disarranges  the  fastenings  and  provokes  their  tearing  out. 
Finally,  if  the  resistance  to  overturning  is  not  assured,  if  the  screw 
spike  does  not  find  a  sufficient  support  in  the  ties,  if  it  is  not  com- 
pletely supported  by  its  flange  on  the  base  of  the  rail,  if  the  rail 
is  pushed  out,  and  that  principally  on  curves,  to  the  exterior  of  the 
curve,  there  is  a  spreading  of  the  track  and  danger  of  accident. 
The  track  is  deformed  in  the  horizontal  direction. 

All  engineers  who  have  made  a  study  of  tracks,  notably  Mr. 
Coiiard,  affirm  that  the  joint  is  the  weakest  point.  Mr.  Freund, 
Engineer  of  Maintenance  for  the  Eastern  Railway  Company,  in  a 
study  of  the  most  interesting  and  best  recorded  facts,  appearing  in 
the  Revue  des  Chemins  de  Fer,  January,  1897,  pointed  out  the  causes 
which  rendered  this  point  the  most  defective. 

There  is  produced  at  the  joints  an  unequal  level  in  the  direc- 
tion of  the  travel  of  the  trains,  that  is  to  say,  at  the  passage  of  the 
vehicles,  the  rail  in  advance  being  higher  than  the  following-rail, 
there  is  a  drop.  This  unequal  level  of  the  rails  at  the  joints  is  the 
result  either  of  the  juxtaposition  of  bars  of  different  height,  or  of 
the  unequal  wear  of  the  splice  bearing  points  of  the  rails  and  the 
splices. 

"The  difference  in  the  head  of  the  rails  is  due  to  the  inevitable 
imperfections  of  rolling.  Sometimes  it  amounts  to  a  millimeter 
from  one  rail  to  another,  and  from  one  extremity  to  the  other  of 
the  same  rail.  It  is  possible,  therefore,  to  produce  jumps  when 
the  chances  of  laying  put  in  juxtaposition,  at  the  same  joint,  the 
extremities  of  the  rails  of  different  caliber. 

"These  jumps  are  ascendant  or  descendant,  in  the  direction  of 
the  movement.  But  whatever  may  be  the  direction  in  which  they 


90  TRACK  DEFORMATIONS. 

are  presented,  they  provoke  shocks  at  the  advance  end  of  the  fol- 
lowing-rail, which  react  on  the  splice  bearing  points  of  that  rail, 
and  promote  its  wear,  while  they  are  without  influence  on  the  bear- 
ing points  of  the  rail  in  advance. 

"As  to  the  inequality  of  the  splice  bearing  points,  already  thus 
prepared,  its  cause  can  be  explained  as  follows,  for  the  part  which 
does  not  arise  from  the  imperfections  of  the  fabrication  of  the 
rails,  and  which  is  clearly  shown  in  the  joints  where  the  rails  are 
of  equal  height. 

"In  consequence  of  the  compressibility  of  the  wood  of  which 
ties  are  made,  of  the  ballast  and  of  the  soil,  the  track  undergoes 
under  the  wheels  of  the  vehicles,  a  depression  which,  almost  in- 
significant under  light  loads,  can  reach  and  even  surpass  0.4  in. 
under  the  most  heavily  loaded  wheels. 

"This  depression  induces  undulations  in  the  rails,  the  amplitude 
of  which,  for  a  given  resistance  of  the  track  to  flexure  or  to  sink- 
ing in  the  soil,  varies  with  the  load  and  the  position  of  the  wheels. 
It  has  in  general,  its  greatest  value  under  the  first  axle  of  the 
engines,  when  that  axle  is  found  in  the  middle  of  two  successive 
supports."  (See  the  article  of  Mr.  Freund,  Revue  des  Chemins  de 
Per  for  January,  1897.) 

It  is  the  successive  undulations  which,  bringing  the  different 
parts  of  the  splicing  in  contact  with  the  extremities  of  the  rail, 
produce  an  abnormal  wear  of  those  parts,  and  determine  the  drop 
of  the  vehicles  from  the  rail  in  advance  to  the  following-rail,  when 
the  latter  pass  over  the  joint.  Thus,  it  results  from  the  examina- 
tion of  a  very  large  number  of  splices  that,  in  consequence  of  these 
oscillations  on  a  line  traversed  in  one  direction,  the  following-rail, 
by  resting  on  the  splicing,  makes  a  kind  of  notch,  b'  (Fig.  19), 
whose  depth  is  at  a  lower  level  than  that  which  the  rail  in  advance 
produces  at  a. 

When  the  load  has  passed  the  joint  and  encounters  the  follow- 
ing-rail, the  latter  is  inclined,  when  resting  at  the  bottom  of  the 
notch,  b',  while  the  rail  in  advance  is  elevated;  there  is  then  a 
considerable  fall  from  the  advance-rail  to  the  following-rail,  as  was 
found  by  Mr.  Coiiard,  and  that  fall  is  due,  except  in  the  case  where 
the  rails  present  an  unequal  height,  to  the  longitudinal  movement 
of  the  track  previously  studied.  The  flexure  of  the  tie  of  the  fol- 
lowing end  of  the  even  joint  ought  also  to  increase  this  effect,  since 
the  more  this  piece  bends,  the  more  is  the  difference  of  level  be- 
tween the  advance  and  following-rails  accentuated.  The  shock 
which  is  produced  at  the  joint  increases  the  flexure  still  more,  be- 


STRESS   OF  TIES    IN   THE   TRACK. 


91 


cause  it  determines  the  unpacking  of  the  cross  tie,  which  is  found 
suspended  at  the  end  of  a  short  time,  and  which  assumes  a  still 
more  pronounced  curve. 

The  cause  of  the  defective  state  of  the  track  at  the  passage 
of  the  joint  being  well  shown  by  the  analysis  of  it  by  Mr.  Freund, 
it  was  of  interest  to  verify  the  manner  in  which  a 'joint  of  a  track 
provided  with  composite  ties  behaves,  in  comparison  with  what 
habitually  takes  place.  If  the  theory  of  Mr.  Freund  is  exact,  the 
fall  ought  to  be  very  much  diminished  when  passing  over  track 
with  composite  ties. 

Care  was  taken  to  observe  the  deformation  of  the  track  befoFe 
any  test,  and  as  it  was  found  that  this  deformation  was  increased, 
the  profile  was  corrected  by  means  of  hoop  iron  wedges  placed  be- 
tween the  splicing  and  the  head  of  the  rail.  Fig.  20  displays  the 
condition  of  the  joints  before  and  after  placing  the  wedges;  the 
latter  have  reduced,  at  least  by  one-half,  the  slope  at  the  extremi- 


Odrance 


Fotlorrinc 


Fig.   19 — Shock  at  the  Joint. 

ties  of  the  rails,  a  slope  which  could  reach  about  .08  in.  in  19.69  in. 
The  permanent  deformation  of  the  rails  was  still  more  apparent 
on  >vack  provided  with  composite  ties  than  on  that  provided  with 
ordinary  ties,  Fig.  21;  that  was  occasioned  by  the  fact  that  the 
P.  M.  rails,  with  which  the  section  was  provided,  were  very  much 
worn,  after  long  service. 

The  experiments  were  carried  on  in  the  following  manner: 
Three  cleats  were  fixed  on  both  sides  of  the  joint,  at  each  of  the 
extremities  of  the  rails,  on  the  upper  part  of  the  head.  A  steel  rule 
placed  on  rigid  supports  allowed  an  estimate  of  the  difference  of 
level  between  the  top  of  the  cleats  and  the  under  part  of  the  rule, 
by  means  of  the  wedge  gage  previously  described.  The  first  axle  of 
the  engine  was  brought  right  at  the  first  cleat,  and  the  profile  of 
the  extremities  of  the  rails  was  observed;  then  the  same  opera- 
tion was  repeated  by  allowing  the  same  axle  to  advance  successively 
right  at  each  cleat,  and  the  same  observation  was  made. 


92  TRACK  DEFORMATIONS. 

The  result  of  these  experiments  is  given  in  Fig.  22,  in  the  left 
part  of  which  are  shown  the  successive  sections  of  profiles  of  th.e 
P.  L.  M.-A.  rails  resting  on  ordinary  cross  ties;  in  the  right  part, 
the  same  profiles  of  P.  M.  rails  supported  on  composite  ties.  The 
full  line  represents  the  original  profile  of  the  rails,  the  dotted  line 
the  profile  deformed  by  the  passage  of  the  vehicle. 

The  original  profile  of  the  P.  L.  M.-A.  rails  is  quite  defective; 
there  is,  from  the  advance  end  to  the  following  end  of  the  joint, 
an  unequal  level  of  .064  in.  at  least;  at  the  passage  of  the  load 
over  the  joint  there  is  a  fall  of  .06  in.  The  successive  profile  of 
the  two  rails  becomes  quite  discontinuous  and  more  undulating. 

The  original  profile  of  the  P.  M.  rails  supported  on  composite 
ties  is  better.  At  the  joint  there  occurs  an  ascending  step,  which 
is  rather  unusual.  The  passage  of  the  load  improves  the  profile, 
which  becomes  almost  continuous;  there  is  an  inequality  of  scarcely 
.012  in.  when  the  load  passes  over  the  joint. 

This  is  what  is  to  be  expected;  it  will  be  recalled,  moreover, 
that  the  longitudinal  movement  of  the  track  is  much  less  strong 
when  the  latter  is  provided  with  composite  ties,  and  that  the  joint 
does  not  undergo  any  oscillation  during  the  passage  of  a  load  over 
the  rail.  The  splicing  is  not  then  injured,  as  in  the  ordinary  case; 
the  shock  which  is  produced  is  very  much  diminished  by  reason 
of  this  fact;  the  following  tie  is  not  unwedged,  at  least  as  rapidly. 
The  unequal  level  of  the  advance  end  and  following  end  is  increased 
by  this  unwedging,  but  the  unwedging  is  also  an  effect  of  the  oscil- 
latory movement  of  the  track,  and  it  becomes,  in  consequence,  one 
of  the  causes  for  bad  condition  of  the  joint.  This  unwedging  causes 
the  tie  of  the  following  end  of  the  even  joint  to  bend  more  than 
otherwise,  which  increases  the  fall  still  more,  due,  for  the  most 
part,  to  the  unequal  wear  of  the  splice  bearing  points.  The  com- 
posite tie,  which  distributes  equally  over  the  ballast  the  pressure 
which  H  supports,  is  not  exposed,  like  the  ordinary  tie,  to  being 
unwedged;  the  fall  at  the  joint  ought  then  to  be  reduced. 

However,  it  is  difficult  to  make  an  exact  and  complete  com- 
parison between  the  results  obtained  on  the  track  provided  with 
P.  L.  M.-A.  rails  and  those  which  have  been  found  on  the  track 
provided  with  P.  M.  rails.  This  latter  track  is  much  more  rigid 
than  the  first,  and  the  movements  which  can  be  produced  are  of 
less  importance.  Similarly,  the  weakness  should  not  reach,  from 
this  fact,  the  proportion  of  1  to  3;  but  it  is  certain  that  it  will 
be  found,  and  will  be  as  much  greater  as  the  tie  is  larger,  and 
as  the  oscillatory  movement  is  reduced. 


STRESS  OF  TIES    IN   THE    TRACK.  93 

The  experiment  performed  under  the  conditions  pointed  out 
is  therefore  of  importance.  The  unequal  level  which  is  produced 
by  the  passage  of  vehicles  from  the  advance  end  to  the  following 
end  has  been  observed  in  the  static  state;  it  is  probable  that  it  is 
greater  in  the  dynamic  state,  by  reason  of  the  shock  which  takes 
place,  and  which  is  capable  of  increasing  the  movement. 

I  have  not  been  able  to  prove  it  on  the  experimental  track; 
moreover,  the  interest  of  such  a  measurement  would  not  have 
been  great,  for  the  track  conditions  on  a  curve  would  have  vitiated 
the  test,,  or,  at  least,  rendered  it  not  precise.  Nevertheless,  I  wished 
to  proceed  with  the  measurement  of  unequal  level  on  track  2  of 
the  line  from  Lyons  to  Geneva,  particularly  stressed  and  provided 
with  P.  M.  rails.  The  ordinary  splices,  which  united  the  extremi- 
ties of  the  rails,  presented  exactly  the  aspect  pointed  out  by  Mr. 
Freund;  that  is  to  say,  the  bearing  points  of  the  splices  were  un- 
equally worn,  and  the  notch  of  the  following  end,  in  consequence 
of  the  repeated  shock,  was  deeper  than  the  notch  of  the  advance  end. 

It  was  necessary,  in  order  to  have  an  exact  proof,  to  photo- 
graph results.  Mr.  Louis  Lumiere,  whose  name  is  well  known  for 
his  optical  studies,  established  a  special  apparatus  of  the  most 
simple  kind,  which  permits  registration  on  a  photographic  film. 
This  apparatus  is  composed  essentially  of  two  acetylene  lanterns  at 
the  center  of  two  concave  mirrors,  each  fixed  to  the  extremities 
of  the  rails  to  be  tested,  and  a  sensitive  film.  The  housing  con- 
taining the  film  and  the  acetylene  lanterns  was  arranged  on  a  con- 
crete block  located  about  a  meter  below  the  track,  in  such  a  man- 
ner as  not  to  be  influenced  by  the  passage  of  vehicles.  The  same 
film  registered  at  the  same  time  the  displacement  of  the  advance 
rail  and  that  of  the  following  rail.  The  experiment  was  performed 
at  the  passage  of  a  freight  train  traveling  at  a  maximum  speed  of 
12.4  miles  an  hour. 

Fig.  23  shows  the  depressions  which  are  manifested  at  the  ex- 
tremities of  the  advance  rail  and  following  rail  at  the  passage  of 
each  of  the  vehicles;  the  absolute  magnitude  of  this  depression 
is  given  by  the  difference  between  the  position  of  the  horizontal 
line  representing  the  luminous  ray  before  the  passage  of  the  train, 
and  the  lower  points  of  the  undulating  line,  determining  for  each 
extremity  of  the  rail  the  oscillatory  movement  which  it  assumes 
at  the  passage  of  the  train.  The  influence  of  each  of  the  axles  is 
clearly  noticeable;  between  two  axles  the  rail  tends  to  raise  up. 
The  same  effect  is  produced  with  more  intensity  between  two  ve- 
hicles. At  the  moment  when  the  train  is  about  to  cross  the  joint, 


94  TRACK  DEFORMATIONS. 

the  rail  is  slightly  elevated,  then  it  is  lowered  by  a  certain  quantity, 
which  appears  maximum  on  the  passage  of  the  first  axle. 

The  magnifying  of  the  upper  record  is  3.79,  the  magnifying  of 
the  lower  record  is  3.91.  It  results  that,  after  the  photographic 
trace,  the  extremity  of  the  following  rail  vibrated  0.35  in.,  and 
that  the  advance  rail  had  a  play  of  0.14  in.  The  fall,  when  pass- 
ing from  the  advance  to  the  following  rail,  would  thus  be  0.21  in. 
It  is  not  necessary  to  remark  that  this  fall  is  very  great,  and  that 
it  indicates  a  joint  in  bad  condition.  It  was  thought  desirable,  in 
order  to  try  the  apparatus,  to  take  a  joint  of  this  kind,  allowing 
an  appreciable  vibration  to  be  obtained.  These  results  are,  besides, 
comparable  with  those  which  are  pointed  out  by  Mr.  Coiiard  in  his 
article  of  July,  1897,  on  the  vertical  deformation  of  the  rails  (Revue 
des  Chemins  de  Fer),  for  he  estimates  that  the  variable  flexure 
of  the  rail  at  its  extremity  is  0.12  in.,  and  that  the  compression 
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then,  0.24  in. 

It  matters  little  whether  the  flexure  does  or  does  not  reach 
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CHAPTER  VII. 

STUDY  OF  WOOD  USED  FOR  TIES. 

Hard  woods  are  principally  used  in  France,  oak  or  beech  being 
preferred,  but  when  these  are  not  easily  obtainable,  or  are  too  ex- 
pensive, pine  is  used;  but  these  woods  are  not  utilized  as  they  are 
found  in  commerce.  They  are  first  submitted  to  preservative  pro- 
cesses, creosote  generally  being  used.  The  timber,  as  purchased,  is 
not  that  of  the  first  quality  used  for  framing — which  costs  in  France 
120  francs  per  cubic  meter,  say  $55  per  thousand  feet  b.m. — but 
second  quality  wood  is  used,  especially  second  quality  oak.  The 
price  of  sap  wood  and  wane  oak,  prior  to  the  preservative  process, 
is  about  $20  per  thousand  feet,  while  beech  costs  about  $16  per 
thousand  feet.  Thus  the  untreated  oak  tie  costs  about  87%  cents 
and  the  untreated  beech  tie  about  68  cents. 

Beech  makes  an  excellent  wood  for  tie  purposes,  but  is  difficult 
to  preserve  and  becomes  worm  eaten  very  rapidly  if  it  is  not  al- 
lowed to  dry  under  favorable  conditions,  especially  if  the  bark  is 
not  removed  after  the  tree  is  cut  down.  Pine  wood  is  quite  resistant 
to  compression  but,  owing  to  the  loose  texture  of  its  fibers,  it  re- 
sists poorly  the  tearing  caused  by  the  fastenings  and  has  a  shorter 
life  in  service  than  the  harder  woods  do  unless  the  fastenings  are 
made  in  a  way  which  will  be  discussed  further  on. 

Mr.  Michel,  Chief  Engineer  of  the  P.  L.  M.  Company,  has  made 
a  study  of  the  relative  compressibility  of  these  species  of  ^YOod  to 
the  limit  of  permanent  deformation.  According  to  him  the  resist- 
ance to  compression  of  oak  or  beech,  common  pine,  larch  or  spruce 
is  as  follows: 

Perpendicular  Parallel  with  the  Proper- 

Species  of  wood.  to  fibers.  fibers.  tion. 

Oak  or   beech 3,413  Ibs.  per  sq.  in.  2,560  Ibs.  per  sq.  in.         .75 

Common  pine    2,845    "      "        "  2,133    "      "        "  .7.", 

Larch  or  chestnut   1,707    "      "        "  1,138    "      "        '•'  .7.~> 

Spruce     1,138    "      "        "  683    "      "        "  .60 

But  this  resistance  to  compression  varies  considerably  according 
to  whether  the  wood  is  treated  or  not,  and  also  according  to  whether 
or  not  it  is  sustained  between  the  walls  of  an  envelope,  as  in  the 
case  of  the  composite  tie.  In  the  first  case,  with  treated  wood, 


STUDY  OF  WOOD  USED  FOR  TIES.  109 

the  resistance  to  compression  diminishes,  as  will  subsequently  be 
shown.  In  the  second  case,  however,  that  of  the  composite  tie,  it 
increases  very  materially  because  the  wood  held  fast  between  the 
walls  of  the  metallic  frame  is  sustained  and  the  fibers  have  less 
play  in  relation  with  each  other. 

But  before  discussing  these  questions  mention  should  be  made 
of  the  process  of  treatment  which  is  employed,  since  this  has  a 
considerable  influence  on  the  durability  of  the  tie  and  consequently 
on  its  steadiness  in  the  track.  The  experiments  made  have  been 
carried  on  principally  with  beech,  but  the  information  derived  can 
easily  be  extended  to  other  kinds  of  wood.  The  quantity  of  creo- 
sote which  can  be  used  depends  upon  the  amount  of  moisture  in 
the  wood  which  is  being  treated;  therefore,  the  seasoning  of  the 
wood  must  first  be  considered. 

In  the  first  experiment,  pieces  of  beech  wood  9.84  ft.  long, 
6.3  ft.  high  and  6.3  ft.  wide  were  cut  immediately  after  the  tree 
had  been  felled  and  were  placed  in  rows  on  supports  under  shelter, 
to  be  seasoned.  These  pieces  of  wood,  which  contained  on  an  aver- 
age 45  per  cent,  of  their  weight  of  water  in  the  beginning,  were 
weighed  separately,  at  first  every  15  days  and  then  at  longer  inter- 
vals. The  successive  losses  of  moisture  are  given  in  the  table  on 
the  following  page. 

This  wood  was  clearly  not  piled  under  conditions,  as  regards 
seasoning,  identical  with  those  of  ties  piled  in  the  ordinary  manner, 
since  these  are  exposed  to  the  weather  and  would  presumably  be 
slower  in  drying,  but  the  extreme  limits  of  seasoning  remain  the 
same;  that  is,  the  maximum  of  moisture  at  the  beginning  will  be 
45  per  cent.,  and  at  the  end  it  will  be  about  21  per  cent.  These 
limits  are  sufficiently  accurate  for  the  discussion  which  follows. 

It  will  be  seen  by  the  table  given  that  nearly  the  maximum 
seasoning  was  obtained  in  4%  months  after  felling,  from  the  first 
of  May  to  the  15th  of  September,  during  the  fine  season.  From 
the  15th  of  September  to  the  15th  of  February  following  the  per- 
centage of  moisture  of  the  wood  remained  stationary  around  22  per 
cent,  with  slight  fluctuations;  then,  during  the  fine  season  follow- 
ing, up  to  October,  1897,  the  rate  of  moisture  descended  to  20  per 
cent. 

According  to  previous  statements,  beech  wood,  after  six  years 
of  seasoning  under  shelter,  still  contained  from  10  to  12  per  cent, 
of  moisture;  but  from  the  point  of  view  of  practical  drying  of  ties, 
it  is  scarcely  possible,  without  stove  drying,  to  lower  it  below  22 
per  cent,  of  moisture. 


110 


TRACK  DEFORMATIONS. 


Periods 

of 
weighings. 

1896. 

1st  May. 
15th  Mav. 


1st  June. 
15th  June. 


Duration 

of 
seasoning. 

Beginning. 


1  month. 


Table   of  Losses   of  Moisture. 

Successive 

proportions  of 

moisture  remaining 

in  the  wood 
at  each  weighing. 


Character  of  wood, 

according 
to  the  degree  of  seasoning. 


1st  July, 
loth  July. 

1st  Aug. 
15th  Aug. 

1st  Sept. 
loth  Sept. 

1st  Oct. 
loth  Oct. 


2  months. 


44.6  per  cent.          From  45  to  40  per  cent,  of  mois- 
38.0        "  ture   some   days   after    felling, 

the  water  flows  from  the  wood 
and  forms  pools  at  the  foot  of 
the  pieces  when  they  are  on 
end. 

31-6        "  From   40  to   35   per  cent,   of  the 

28.6  wood      still     surcharged      with 

water  appears  translucent  at 
the  surface,  when  it  has  just 
been  cut ;  the  fresh  shavings 
are  semi-transparent  when  in- 
terposing them  between  the 
eye  and  the  light. 


26.5 
24.5 
23.0 
22.5 

22.0 
21.8 

21.7 
21.6 


1st  Nov. 

1st  Dec. 
1897. 
1st  Jan. 

1st  Feb. 


Below  30  per  cent,  moisture,  it  is 
difficult  at  first  sight  to  state 
the  degree  of  seasoning. 

With  20  per  cent,  of  moisture,  it 
can  be  said  with  certainty  that 
the  wood  has  arrived  at  its 
maximum  practical  seasoning 
without  stove-drying,  because 
it  will  scarcely  dry  more  when 
exposed  to  the  air  another  year. 

6  "  It  is  probable  that  the  ties  in  the 

middle   of  a  pile  could  not  at- 

7  tain   this  degree  of  seasoning. 

8  "  ....  The  wood  after  5   to  6  years  of 

seasoning    under    shelter,    still 

9  "  21.8  per  cent.  contains  10   to   12  per  cent   of 

moisture. 

The  quantity  of  water  contained  in  pine  is  at  least  equal,  if 
not  greater  than,  that  which  is  found  in  beech,  that  is  to  say  about 
45  per  cent,  immediately  after  felling  and  20  per  cent,  after  season- 
ing. It  is  not  the  same  in  the  case  of  oak;  the  percentage  of  moist- 
ure which  it  possesses  is  certainly  less,  the  fibers  of  the  wood  are 
more  compressed,  and  the  quantity  of  water  which  they  enclose 
more  restricted.  It  is  difficult  for  me,  for  want  of  precise  experi- 
ments, to  give  an  exact  figure;  it  can  be  said,  however,  that  this 
wood  dries  very  slowly,  keeps  its  moisture  a  very  long  time,  and 
absorbs,  consequently,  a  very  small  quantity  of  creosote.  On  this 
account,  it  is  difficult  to  say  when  the  preservation  process  can  best 
be  undertaken.  This  refers  to  the  heart  of  the  wood,  not  to  the 
sap,  which  loses  its  water  very  rapidly. 


STUDY  OF  WOOD  USED  FOR  TIES. 


Ill 


When  cross  sections  of  new  beech  cross  ties  creosoted  with 
35  Ibs.  and  containing  much  moisture  (30  per  cent,  for  example, 
which  is  very  common),  are  immediately  examined  after  the  injec- 
tion has  been  made,  it  is  noticed  that  the  creosote  has  penetrated 
into  the  end  by  the  annual  layers  of  the  autumn  wood,  and  that 
the  spring  wood,  though  considered  more  porous,  has  not  been  abso- 
lutely impregnated;  the  wood  resembles  a  series  of  concentric  rings 
alternately  creosoted  or  intact. 

The  sections,  made  quite  near  the  extremities,  show  the  wood 
impregnated  for  a  certain  distance  without  alternations;  at  3.94  in. 
the  rings  commence  to  be  denned,  7.87  in.  they  are  very  clear,  and 
occupy  nearly  the  whole  section  of  the  wood.  (Fig.  24.) 


Fig.  24. 


Fig.  25. 


Fig.  26. 

But  proceeding  towards  the  mortises  for  plates,  the  notable 
portions  of  these  rings  disappear  (Fig.  25)  and  become  more  rare 
in  proportion  as  they  approach  the  middle  of  the  length,  where, 
often,  there  is  no  longer  any  trace.  (Fig.  26.) 

On  the  other  hand,  it  is  seen  that  the  creosote  has  also  pene- 
trated through  the  lateral  surface,  by  reason  of  the  degree  of 
moisture  in  the  wood;  above  35  per  cent,  there  is  almost  no  more 
penetration,  scarcely  two  to  three  millimeters  (0.08  or  0.12  in.), 
sometimes  none;  towards  30  per  cent,  the  creosote  has  penetrated  to 
:a  depth  of  two  to  three  millimeters  (0.08  to  0.12  in.),  for  the  color 
'Of  the  wood  goes  on  getting  weaker  in  the  direction  of  the  depth. 


112  TRACK  DEFORMATIONS. 

In  the  moist  wood,  as  above,  there  exist  few  cracks  arising 
from  seasoning;  when  they  are  observed  they  are  in  the  direction 
of  medullary  rays,  not  penetrating  to  more  than  two  to  three  cen- 
timeters (0.79  to  1.18  in.),  and  the  creosote  has  penetrated  a  little 
deeper  by  them.  These  cracks  do  not  follow  the  meshes,  but  form 
freely  among  them. 

If  a  transverse  cut  is  made  at  the  extremity  of  a  beech  tie  in- 
jected with  35  IDS.,  freshly  creosoted  in  the  moist  state  (30  per  cent. 
for  example),  it  is  observed  that  the  concentric  rings  of  the  annual 
layers  form  alternations  of  wood  creosoted  and  not  creosoted;  but 
by  leaving  the  piece  of  wood  of  small  sectional  volume  in  the  air, 
the  rings  of  creosote,  clearly  limited  and  defined  on  the  cut  sur.face, 
spread  out  by  the  seasoning  and  the  creosote  is  diffused  in  the  cir- 
cular intervals  of  wood  previously  intact.  When  this  piece  of  wood 
has  finished  drying  (which  requires  one  or  several  days,  according 
to  the  thickness  of  the  piece  and  the  temperament),  the  creosote  is 
diffused  in  a  diluted  greenish  tint,  which  sometimes  occupies  the 
whole  mass.  In  the  sections  of  these  moist  ties  made  towards  the 
mortises  for  plates,  or  towards  the  middle  of  the  tie,  are  parts  the 
least  injected,  where,  at  the  moment  of  making  the  section,  only 
small  portions  of  wood  creosoted  are  seen,  the  diffusion  on  drying 
is  exceedingly  slight. 

But  if  these  samples  of  wood  imperfectly  creosoted  are  pre- 
served in  moist  sand,  no  diffusion  apparently  takes  place.  Accord- 
ing to  that  it  would  seem  that  there  was  advantage,  for  the  dif- 
fusion of  the  creosote,  in  keeping  the  ties  after  creosoting  exposed 
for  a  long  time  to  the  air,  but  it  is  observed  that  this  diffusion, 
which  is  well  done,  and  within  a  short  time,  with  the  small  samples, 
is  much  slower  with  the  ties  exposed  to  the  air. 

On  the  other  hand,  the  tie  from  which  the  piece  in  question 
has  been  cut,  is  preserved  even  in  the  air  with  its  tints  in  rings, 
without  any  diffusion,  during  several  months,  and  to  such  a  degree 
that  it  keeps  at  least  30  per  cent,  of  its  original  moisture;  once 
placed  and  buried  in  the  ballast,  it  losses  or  absorbs  moisture  very 
slowly,  according  as  it  is  more  moist  or  more  dry  than  the  medium 
surrounding  it  when  it  is  first  placed  in  the  track.  When  it  has 
reached  the  degree  of  moisture  of  the  ballast,  the  latter  diminishes 
or  increases  according  to  the  seasons.  In  ties  weakly  creosoted 
with  35  Ibs.  in  pure  gravel  ballast,  in  position  for  at  least  five 
years,  the  wood  not  injected,  in  the  interior  of  the  tie,  contained 
from  30  to  35  per  cent,  of  moisture  in  the  month  of  September, 
after  a  month  of  dryness  and  an  ordinary  summer;  in  a  ballast 


STUDY  OF  WOOD  USED  FOR  TIES.  113 

of  broken  stone  this  proportion  of  moisture  is  much  less,  from  20 
to  25  per  cent.,  which  favors  diffusion. 

In  these  kinds  of  ties  the  impregnation  is  generally  produced 
by  the  rings  of  autumn  wood;  it  was  not  diffused,  and  the  rings, 
although  compared,  remained  in  their  primitive  state.  The  limit- 
ing amount  of  moisture  at  which  the  diffusion  commences  to  work 
is  not  known,  but  it  is  evidently  less  than  30  per  cent. 

When  the  amount  of  creosoting  is  reduced  from  46  to  35  Ibs., 
beech  ties  are  imperfectly  creosoted,  and  the  white  wood*  not 
creosoted  appears  on  the  mortise  for  the  plate,  that  is  to  say,  at 
a  distance  of  a  centimeter  (0.39  in.)  from  the  surface.  With  the 
aid  of  a  special  auger,  numerous  samples  of  untreated  wood  were 
taken  from  these  ties,  and  from  30  to  35  per  cent,  of  water  was 
found.  When  they  have  30  per  cent,  moisture  they  are  only  super- 
ficially creosoted,  except  at  the  extremities  over  9.84  in.  long,  where 
the  injection  has  penetrated  without  reaching  the  mortises  for  plates. 
Some  ties  of  this  nature  employed  in  the  annual  track  renewals 
from  1889  were  submitted  to  a  special  examination.  By  sounding 
them  from  time  to  time  it  was  proved  that  they  were  rapidly  worm- 
eaten,  and  that  at  the  end  of  four  years  a  large  number  of  them, 
from  15  to  30  per  cent.,  according  to  their  position  in  the  track, 
commenced  to  decay  in  their  interior;  10  per  cent,  were  already 
replaced  at  the  end  of  this  short  lapse  of  time. 

In  all  the  ties  studied,  the  decay  followed  the  same  course. 
There  is  first  produced  the  heating  or  the  spotting  of  the  wood  not 
creosoted,  situated  immediately  under  the  superficial  crust  pene- 
trated with  creosote,  and  that  over  the  upper  part  of  the  tie,  which 
is  not  covered  up  and  is  placed  in  the  interior  of  the  track.  The 
spotted  wood  is  that  which  has  heated  before  seasoning  by  the 
fermentation  of  the  sap  moisture;  in  the  beginning,  the  color, 
generally  clear  yellow  for  beech  wood,  commences  to  be  spotted 
with  characteristic  white  points,  then  to  be  marbleized  with  yellow- 
ish spots;  the  fibrous  contexture  disappears,  the  wood  becomes 


*The  wood,  which  remains  with  its  natural  color  without  any  trace  of  in- 
jection, is  called  white  wood  in  beech  ;  the  most  common  color  of  beech  is 
clear  yellow  ;  it  is  often  white  as  poplar  ;  exceptionally,  it  is  reddish.  The 
heart  wood,  which  appears  towards  the  age  of  30  to  35  years,  is  red,  very  hard 
and  appears  to  be  proof  against  the  injection  of  an  amount  of  33  Ibs.  Un- 
treated heart  wood  is  not  found  in  the  cross  ties  of  1877,  subjected  to  55  Ibs. 
of  creosote.  All  the  wood  in  these  old  ties  is  strongly  impregnated  with 
creosote.  The  whole  of  the  wood  is  strongly  impregnated  with  creosote.-— 
From  the  report  of  Prof.  W.  K.  Hatt,  to  the  American  Railway  Engineering 
and  Maintenance-of-Way  Association. 


114  TRACK  DEFORMATIONS. 

spongy,   becomes  yellow  colored,*  and  the   shavings  which  are  cut 
have  no  body  and  crumble.     (Fig.  27.) 

The  next  process  is  that  the  heating  gains  in  depth  and  reaches 
.all  wood  not  creosoted,  which  affects  the  shape  of  a  spindle  on  the 
longitudinal  section  of  the  cross  tie,  and  is  terminated  in  a  fish 
tail  towards  the  fastenings;  the  wood  which  is  spotted  and  has  first 
become  yellow  under  the  creosote  crust  of  the  surface,  still  intact, 
assumes  a  brown  color,  of  touch-wood,  and  seems  to  be  calcined. 
The  tie  preserves  a  very  good  appearance  on  the  exterior,  and  the 
•wood  under  the  fastenings  remains  quite  sound.  (Fig.  28.) 

The  creosoted  superficial  crust  of  the  top  next  yields  and  is 
broken  towards  the  middle  of  the  inter-rail  space;  it  forms  a  trough 
in  the  decayed  wood,  where  water  accumulates,  and  promotes  decom- 
position. The  decay  reaches  the  fastenings  more  or  less  rapidly, 
which  often  hold  sufficiently  well,  above  all  those  of  the  exterior, 
but- the  tie  is  out  of  service.  (Fig.  29.) 

Some  hundreds  of  decayed  ties  taken  out  of  the  track  have  been 
examined,  and  samples  were  taken  from  more  than  10,000  ties  in 
service,  commencing  to  decompose;  the  same  process  of  decomposi- 
tion has  always  been  observed  in  ties  injected  with  35  Ibs.  Beech 
wood  very  sound,  but  moist  with  sap,  not  injected,  imprisoned  in 
the  superficial  bed  of  creosoted  wood,  which  prevents  that  sap 
from  evaporating,  becomes  heated  and  decays  rapidly  by  commencing 
at  the  part  contiguous  to  the  face  free  from  ballast,  exposed  to  the 
sun,  which  first  becomes  spotted. 

A  very  conclusive  experiment  was  tried  on  this  subject,  which 
is  easy  to  repeat;  there  was  available  in  the  spring  a  half  tie  of 
very  sound  beech  of  recent  felling,  containing  35  to  40  per  cent, 
of  sap  water.  Two  pieces,  each  27%  in.  long,  were  taken  from  it; 
after  having  tarred  the  first,  it  was  buried  in  the  ballast,  leaving 
the  upper  face  uncovered,  exposed  to  the  air,  and  the  other  piece, 
not  tarred,  was  preserved  as  a  witness,  exposed  to  the  air  but  not 

*When  the  natural  beech  wood  (not  creosoted)  becomes  spotted  it  loses 
its  clear  yellow  color  and  passes  to  straw  yellow  or  citron  yellow,  and  its 
fibrous  texture  disappears.  It  becomes  spongy  and  in  planing  the  shavings 
have  no  body  and  crumble  away.  It  breaks  with  the  least  effort,  "like  a 
radish,"  that  is  to  say,  the  fracture  does  not  present  drawn  out  fibers  as  are 
produced  with  sound  wood  ;  to  use  a  local  expression,  it  is  "cooked."  In  this 
state,  which  is  always  the  prelude  of  the  red  decay,  the  screw  spikes  no  longer 
hold  well  in  the  tie,  but  turn  without  effort. 

The  yellow  wood  in  question  contains  no  trace  of  creosote,  as  the  analysis 
of  the  shavings  shows.  However  diluted  the  creosote  may  be,  the  traces  are 
easily  observed,  even  in  wood  very  lightly  tinted,  or  by  compressing  the  wood 
in  a  press  between  two  leaves  of  white  blotting  paper,  or  better,  by  treating  it 
with  benzine. 

Both  yellow  wood  and  "cooked"  wood  are  stages  of  decay. 


STUDY  OF  WOOD  USED  FOR  TIES.  115 

buried.  At  the  end  of  six  months  the  first  piece  was  unburied,  and 
it  Was  observed  while  cutting  it  that  it  was  heated  and  entirely 
spotted  in  the  interior,  but  particularly  under  the  uncovered  face 
exposed  to  the  sun,  where  the  decomposition  was  remarkably  much 
more  advanced.  The  proof  piece  remained  perfectly  sound,  and  was 
dry;  the  other,  on  the  contrary*  had  kept  all  of  its  moisture.  That 
is  what  takes  place  in  ties  whose  injection  is  only  superficial. 

In  order  to  make  the  creosote  penetrate  better  into  that  part 
of  the  tie  which  receives  the  screw  spikes,  the  cutting  and  the  boring 
are  performed  before  injection,  and  this  practice  has  been  followed 
in  France,  in  a  general  way,  since  1894. 

By  comparing,  by  means  of  longitudinal  sections  and  samples, 
previously  taken  from  different  points  of  their  length,  the  ties  in- 
jected after  this  procedure  with  those  injected  without  holes,  it  is 
observed  that  the  first  are  impregnated  with  creosote  under  the 
mortise  and  in  the  region  of  the  holes;  but  the  second  are  injected 
only  at  a  distance  from  the  extremities,  which  varies  with  the  de- 
gree of  humidity  of  the  ties  at  the  moment  of  injection,  which  often 
does  not  reach  the  mortise.  And  as  the  creosoted  wood  is  not 
reached  by  decay,  and  as  a  single  fiber  of  injected  wood  remains 
unimpaired  in  a  center  of  decomposition,  we  are  assured  that  boring 
the  ties  before  injection  increases  their  durability,  and  that  it  is  a 
good  practice. 

Independently  of  the  experiments  related  above,  Mr.  Ferry  has 
made  others  on  thousands  of  ties,  developing  the  same  facts.  We 
will  cite  only  one  to  show  the  influence  of  creosoting  to  refusal. 

Of  1,152  beech  ties,  injected  after  this  manner,  and  placed  in 
1877  on  the  line  from  Mouchard  to  Bourg,  between  kilometers 
492,024  and  493,000,  all  were  as  sound  in  1896,  that  is  to  say,  19 
years  after  placing  them,  as  on  the  first  day,  while  1,204  ties  placed 
in  1889  on  the  same  line,  which  were  only  injected  with  37%  Ibs. 
per  tie,  were  entirely  decayed,  in  the  proportion  of  35  per  cent.,  at 
the  end  of  six  years. 

The  conclusion  to  be  drawn  from  these  experiments  is  that  ties 
are  generally  creosoted  very  superficially,  for  the  reason  that  it  is 
not  possible  to  obtain  a  complete  drying  for  the  extraction  of  all 
the  water  which  they  contain.  Even  by  stove  drying,  the  operation 
cannot  be  pushed  sufficiently  far  to  remove  all  the  sap;  we  must 
therefore  be  contented  with  allowing  the  ties  to  dry  naturally,  which 
always  shuts  up  a  certain  quantity  of  water,  particularly  in  their 
center. 

Injection  practiced  after  an  imperfect  drying  has  also  the  effect 


O) 


O) 

il 


m 


STUDY  OF  WOOD  USED  FOR  TIES.  117 

•of  concentrating  the  water  in  that  part,  which  becomes  consequently 
a  center  of  decomposition  for  the  tie.  Each  tie  then  commences  to 
decay  in  its  center,  which  is  the  part  exposed  to  the  alternatives 
of  heat  and  dryness,  while  the  extremities,  better  creosoted  and 
.under  protection  of  the  ballast,  resist  for  a  longer  time. 

TREATMENT    OF  PINE   AND  OAK. 

The  same  process  which  has  been  found  for  beech  is  applicable 
for  pine;  the  latter  ought  even  to  absorb  a  greater  quantity  of  creo- 
sote. The  same  thing  does  not  hold  true  with  oak;  the  heart  of 
the  oak  only  takes  traces  of  creosote,  only  the  sap  being  pene- 
trated by  the  injection.  But  this  hard  fiber  is  sometimes  a  disad- 
vantage instead  of  an  advantage;  for  if  the  heart  of  the  oak  is  not 
dry  (and  it  is  hard  to  tell  whether  it  is  or  not),  the  envelope  of 
•creosote  prevents  the  slow  evaporation  of  the  sap,  which 
finishes  by  being  decomposed,  and  attacks  in  its  depth  the  wood 
•of  most  sound  appearance.  That  is  the  cause  of  decay  of  the  great- 
est number  of  ties,  every  piece  of  wood  having  more  than  20  per 
cent,  moisture,  and  covered  over  with  a  superficial  bed,  rapidly 
deteriorates,  the  beech  at  the  end  of  three  months,  the  oak  at  the 
end  of  a  longer  period. 

The  heart  of  the  oak,  which  only  absorbs  a  very  small  quantity 
of  creosote  because  of  its  persistent  state  of  moisture,  is,  however, 
susceptible  of  decay  from  a  cause  other  than  that  of  its  superficial 
envelope  preventing  the  slow  and  gradual  evaporation  of  the  sap. 
The  wood  is,  in  fact,  generally  very  much  cracked;  under  the  action 
of  atmospheric  variations,  these  fissures  open  gradually  wider  and 
form  a  kind  of  trough,  where  the  water  enters  vertically.  At  the 
•end  of  a  certain  time  this  succession  of  moisture  and  of  dryness 
favors  the  development  of  fungi,  and  produces  work  of  decomposi- 
tion in  the  wood,  which  always  perishes  in  its  central  part,  gen- 
erally not  covered  over.  It  is  worth  while  remembering  that  the 
simple  bed  of  ballast  placed  on  the  breech  of  the  tie,  the  plate  placed 
under  the  rail,  protects  the  wood  in  an  efficient  manner  against  this 
kind  of  decomposition.  This  evidently  arises  from  the  fact  that, 
in  the  case  of  ties  drying  rapidly,  like  those  of  beech,  the  creosot- 
ing  is  more  complete;  but  in  the  case  of  oak,  which  is  only  made 
superficially  antiseptic,  the  fissures  do  not  form  as  in  the  uncovered 
central'  part,  and  the  decomposition  of  the  wood  is  not  produced. 

The  preparation  of  wood  before  injection,  and  the  proper  drying 
•of  it,  are  very  important.  The  amount  of  the  injection  ought  equally 
.to  enter  into  the  computation,  for  if  it  is  insufficient,  it  prolongs 


118  TRACK  DEFORMATIONS. 

but  little  the  durability  of  the  piece  of  wood.  Results  from  actual 
experiment  explain  why,  in  spite  of  the  expense  which  it  induces,, 
the  amount  of  creosote  used  has  tended  constantly  to  be  increased.* 

In  order  to  obtain  satisfactory  results,  it  was  necessary  to  reach 
refusal;  a  point  which  is  not  absolute,  and  depends  even  upon  the 
dimension  of  the  piece  submitted  to  injection.  Thus,  the  beech 
ties,  8.86  ft.  long  and  of  ordinary  dimensions,  scarcely  take  55  Ibs., 
even  to  saturation;  the  pieces  of  more  restricted  dimensions,  like 
the  blocks  of  composite  ties,  absorb  a  greater  quantity  of  creosote 
— 20  per  cent,  more — because  the  water  of  sap  is  more  completely 
eliminated.  These  pieces  can  then  become  indestructible  and  in- 
variable in  volume,  as  has  been  stated,  whatever  may  be  the  agents. 
to  which  they  are  submitted.  The  sap  water  having  been  replaced, 
or  surrounded  by  an  antiseptic  substance,  the  body  is  as  though 
mummified,  without  undergoing  any  alteration  in  the  future.  This 
is  what  explains  that,  in  spite  of  the  variations  in  temperature, 
the  blocks  are  maintained  for  nearly  four  years  in  the  metallic 
skeletons  without  undergoing  any  modifications. 

Experiments  permit  us  to  state  these  general  points  precisely; 
two  pieces  of  beech  were  taken,  one  from  a  tree  felled  in  the  month 
of  December,  1902,  whose  dimensions  were:  Length,  271/-_>  in.;  width, 
9.8  in.;  depth,  5.9  in.,  and  they  were  placed  under  observation. 
When  they  had  attained  the  degree  of  seasoning  of  20  per  cent.,, 
presenting  then  at  their  extremities  important  longitudinal  clefts,. 
they  were  submitted  to  two  successive  injections  of  creosote  in  such 
a  manner  that  they  absorbed  the  greatest  possible  quantity  of  it. 
The  four  faces  of  each  of  the  blocks  on  three  different  sections. 
were  previously  referenced  to  the  tenth  of  a  millimeter;  they  were 
referenced  anew  after  the  creosoting.  The  absorption  of  the  creo- 
sote, at  the  rate  of  18.7  Ibs.  per  piece  of  wood,  produced  a  mean 
elongation  of  each  face  of  0.04  in.  and  the  fissures  were  completely 
closed.  The  void  existing  in  a  piece  as  dry  as  possible  is  then  very 
small,  scarcely  0.04  in.  on  each  of  its  faces;  it  is  the  maximum 
play  which  can  take  place  in  the  wood  when  it  passes  from  the  dry 
to  the  humid  state,  or  inversely.  But  with  an  injection  to  refusal 
there  is  no  play  to  fear,  since  the  pores  of  the  wood  are  filled  up 

*Amount  of  creosoting  reported  : 

Oak.  ^ 11  to  15. 4  Ibs.  per  cross  tie.      (Refusal.) 

C     28.6  Ibs.  The  Northern  Co. 
Ma  to  35  Ibs.  The  Western  Co. 
1       35  Ibs.  The  P.  L.  M.  Co. 


52.8  Ibs.  (Refusal.)  The  Eastern  Co. 

The  Midland  Co. 

Tine -\      30.8    "  The  Orleans  Co. 

The  P.  L.  M.  Co. 


^  »J-..O    1  UI5, 

•f  20.4     - 

-j  30.8    " 

I  LM5.4     '• 


STUDY  OF  WOOD  USED  FOR  TIES. 


119 


and  can  absorb  no  more,  and  since,  on  the  other  hand,  the  block 
protected  by  the  metallic  skeleton  will  not  give  up  any  part  of  the 
liquid  absorbed. 

I  treated,  like  the  beech,  four  blocks  of  heart  oak;  these  pieces 
of  wood  did  not  absorb  any  appreciable  weight  of  creosote,  scarcely 
0.44  Ibs.  each;  that  is  to  say,  a  quantity  scarcely  sufficient  to  coat 
them  superficially. 

Finally  the  wood,  dried  to  an  .amount  inferior  to  20  per  cent, 
by  means  of  stove  drying,  for  example,  and  replaced  in  air,  regained 
moisture  in  a  short  time  so  as  to  reach  the  amount  of  20  per  cent. 
That  which  we  will  designate  as  dry  wood  will,  then,  be  wood  con- 
taining 20  per  cent,  of  its  weight  of  water. 


INFLUENCE    OF    CREOSOTING    ON    THE    RESISTANCE    TO    COMPRESSION. 

But  if  creosoting  has  given  favorable  results  from  the  point 
of  view  of  the  preservation  of  the  wood,  it  acts,  on  the  contrary, 
in  an  injurious  way,  to  diminish  the  resistance  of  the  piece  sub- 
mitted to  compression.  Mr.  Ferry  has  made  a  series  of  very  inter- 
esting experiments  on  the  resistance  to  compression  of  pieces  of 
wood  submitted  or  not  to  an  injection  of  creosote,  and  placed  either 
in  the  direction  of  the  fibers  or  perpendicular  to  that  direction.  An 
apparatus  constructed  by  Mr.  Collet  was  employed  to  produce  this 
compression,  and  which  permitted  a  pressure  of  8.8  net  tons  to  be 
reached;  the  wood  was  experimented  with  under  the  form  of  cubes 
of  2%  in.  each  way.  The  results  of  the  experiments  are  summarized 

in  the  table  below: 

Deformation  when  load  is 
applied  perpendicular  to 


Dry  oak  

Load, 
Ibs. 
per  sq.  in. 
.  .      1,741 
.  .      1,741 
.  .      1,741 
508 

,  thefl 
Following 
the  Medullarj 
rays. 
0.00290  m. 
0.00160  m. 
0.00287  m. 
0.00314  m. 

bers  x 
Perpendic- 
r      ular  to           Deformation  of 
those  rays.          wood  on  end. 
0.00380m.              0.00117m. 
0.00350  m.               
0.00334  m.*           0.00105  m. 

Dry  beech  
Creosoted  beech  .  .  . 
Spruce 

Spruce 

.  .      1,741 

0  000875  m 

^Deformation  obtained  with  1,306  Ibs.  per  sq.  in. 

These  figures  have  not  an  absolute  value,  but  a  relative  value, 
for  it  would  be  necessary,  to  obtain  the  former,  to  take  account  of 
the  deformation  of  the  apparatus  itself,  which  has  an  influence  on 
the  results.  What  we  should  keep  in  mind,  nevertheless,  is  that 
the  deformation  varies  within  sufficiently  large  limits,  according  to 
whether  the  force  is  exerted  perpendicular  to  the  fibers  of  the  wood, 
to  the  medullary  rays,  or  else  in  a  perpendicular  direction  to  those 


120  TRACK  DEFORMATIONS. 

rays;  finally,  according  as  it  is  produced  on  the  wood  on  end.  Spruce 
resisted  the  best,  at  least  in  the  perpendicular  direction.  The  de- 
formation in  this  direction  would  be  about  once  and  a  half  greater 
than  it  is  in  the  perpendicular  direction,  that  is  to  say,  following 
the  medullary  rays.  The  deformation  is  accentuated  when  the  wood 
is  injected  by  about  double;  the  liquid  injected  exudes  at  the  same 
time  that  the  increase  of  pressure  is  produced.  In  every  case  the 
deformation  of  the  piece  of  wood  takes  a  particular  form:  the  spring 
layers,  which  are  the  most  tender,  crush,  and  the  autumn  layers, 
which  are  the  hardest,  slide  over  the  first,  giving  the  aspect  of  a 
series  of  checks. 

These  phenomena  are  manifested  when  the  wood  is  in  a  free 
state;  it  does  not  seem  that  it  should  be  thus  when  the  wood,  sub- 
mitted to  compression  following  the  medullary  rays,  is  prevented 
from  being  deformed,  whether  it  be  shut  up  in  a  skeleton  which 
sustains  it,  or  whether  it  be  maintained  in  the  transverse  direction 
by  a  counter  pressure.  In  this  case  it  acquires  a  superior  resist- 
ance and  does  not  allow  itself  to  be  easily  deformed  because  it  is 
sustained. 

That  is  what  I  have  observed  on  composite  ties  by  comparison 
with  ordinary  ties.  It  is  recalled  that  the  blocks  of  the  composite 
tie  are  pressed  between  the  walls  of  the  skeleton  by  means  of  cross 
bars,  and  that  the  skeleton  is  thus  shut  up  on  these  pieces  of  wood 
in  order  to  compress  them.  It  is  thus  possible  to  appreciate  the 
influence  of  the  compression  of  the  wood  in  default  of  direct  experi- 
ments. 


CHAPTER  VIII. 

METHODS    FOR    REMEDYING    TRACK    DEFORMATION. 

After  having  studied  the  principal  deformations  to  which  the 
track  is  submitted,  it  is  proper  to  summarize  the  causes  which-  have 
produced  them  and  to  search  for  methods  to  remedy  them. 

We  have  seen  that  the  deformations  consist  of  the  creeping 
of  the  track,  the  reduction  in  gage  of  the  track,  or  its  spreading, 
the  compression  of  the  supports,  the  extraction  of  the  screw  spikes, 
which  contributes  to  the  vertical  deformation  of  the  rails,  and  finally 
of  the  shock,  which  is  produced  right  at  the  joint,  and  which  renders 
the  latter  the  worst  point  in  the  track.  We  have  set  aside  in  this 
enumeration,  which  is  not  necessarily  complete,  the  sliding  of  the 
track,  which  is  exercised  in  a  peculiar  manner,  and  has  no  rela- 
tion with  the  deformations  in  question.  The  latter,  as  also  those 
we  have  pointed  out,  are  due  to  two  principal  causes:  the  flexure 
of  the  tie  and  the  longitudinal  movement  of  the  track,  this  last 
movement  being  itself  a  function  of  the  flexure.  Recapitulating, 
it  is,  therefore,  the  reduction  of  the  effect  of  these  two  causes  to 
which  all  specialists  should  bend  their  efforts.  But,  before  exam- 
ining in  detail  the  proper  means  for  diminishing  the  importance 
of  this  effect,  it  is  necessary  to  give  an  account  of  the  manner  in 
which  the  tie  rests  on  the  ballast,  because  its  position  in  the  bal- 
last ought  to  fix  the  tamped  bed  which  should  be  made,  and  the 
length  to  give  to  it. 

It  follows  from  numerous  statements  which  we  have  worked 
out  that  the  tie,  however  well  tamped  it  may  be,  and  of  whatever 
length,  gives,  at  the  end  of  a  certain  time  after  the  passage  of 
trains,  the  same  form  of  flexure  to  the  ballast  which  it  experiences 
(see  Figs.  30,  31  and  32).  This  flexure  we  have  made  known  above; 
it  is  either,  if  the  tie  is  long  (more  than  7.54  ft.),  a  concave  curve 
with  light  swelling  in  the  center,  or  else,  if  the  tie  is  short  (less 
than  6.88  ft.),  a  convex  curve.  This  deformation  of  the  ballast  is 
not,  as  has  been  thought,  an  elastic  deformation,  but  entirely  per- 


122 


TRACK  DEFORMATIONS. 


F-  

-^£3  

<gmjKTO?T1FKTOirwraT!!S!!5^sr 
_^ISP-             —  . 

[  

ffSjL  4  J 

j< /S.7S-—  -4f /£7S-  —  *\ 

fbrf  Tamped  with  Tamping- Bar 


(<__  _/$•  7S- — * /£7S' — >,: 

Part  Tamped  irm  Tamping  Bar 


off/re  bee/ 

for  laying  rrea'&ea'  by  tamping  am  me  rammer: 
The  parts  not  hatched  are  simp/y  fitted  tr/th 
ballast  not  compressed  ttfttt  trie  rammer: 


Note:  The  hate  fiing  indicates  the  parts 
''          mping  am 


Wood  Tie  Normally  Tamped.  (Track  without  e/eraf/on) 
Arrangement  of  tamping  rrhen  if  has  jusf  £ee,i  efo.ie  ana" 
before  the  passage  offra/rf. 


Wood  Tie  Normally  Tamped.  (Track  w/fhouf  e/eraf/'on) 
Arrangement  of  tamping  afferafraff/'c  of  SOO  fra/'ns. 

note:    Tfie parts  ab  become  spontaneously  wedged  a  short  time  after /ay/'rtg. 
The  doffed  fine  is  the  curre  of  maximum  flexure  unc/er/oad. 

There  exists  in  repose,  between  the  lover  face  of  the  fie  and  the  bed  for  /aySng/n  6a//vst,  a  space  r/n  tfie  form  of  a  bas/n  on  nrh/'ch 
is  moti/ded  at  the  moment  of  foadlng  the  face  of  f/>/s  fie,  which  continues  ro  descend  eran  to  the  c/otfea' //rre.     Th/s  socrce  rar/es  from 
$  of  a  millimeter  to  /  m/m  according  fofhe  /rate/re  of tfie  6a//asf.      The  S/exvre  wafer  tte /acre*  ef  is  arr  arercrq'e  of  2^/m  for- 
the  ft  ft.  track  /aid  at  L  +  4. 


Wood  Tie  Norm  a  f ft/  Tamped    (Track  ny//?  e/eraf/on  of  3.27  ftacf/t/s  /9&3.Sff.) 


Composite  Tie  Normal fy  Tamped.  (Track  with  e/eration  of  3.27f?ad/us 

Arrangement  of  tamping  offer  a  traffic  of  SOO  trains. 
Note:    The  composite  tie  is  only  tamped  under  the  block  extending  for  J3.  T3"on  each  side  of  the  raif.    The  rest  is  empty.     The  tcrmp/figr 
with  the  tamping  bar  from  the  beginning  does  not  become  mod/tied  #ith  ttme.  and  no  iro/d/s  observed  beneath  the  fre  in  repose,  as  fo#rs 
place  in  the  case  of  the  wood  f/e. 


Comparafiye  Flexure  under  Load  off  he  Compost fe  and  Wood  T/'es.     Track  triM  e/eraf/orr  of  3. 2  7 ' 

Radius  /9&3.Sf7:) 

Figs.  30,  31   and  32. 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       123 

manent,    which    remains   when    the    cause    which    produced    it   has 
ceased. 

The  ballast,  in  spite  of  all  contrary  appearances,  is  not  elastic; 
it  subsides  successively  and  little  by  little  under  the  passage  of 
vehicles.  This  subsidence  is  variable  according  to  the  nature  of 
the  ballast  and  the  state  of  the  subsoil,  and  amounts  to  1.18  or 
1.57  in.  when  it  is  a  question  of  gravel  and  a  subgrade  capable  of 
deformation  (embankment  and  cut  argillaceous),  and  some  milli- 
meters only,  when  the  ballast  is  composed  of  broken  stone,  and 
when  the  subgrade  resists  more  completely.  Thus  it  would  seem 
that  the  track  ought  to  descend,  and  by  appreciable  quantities;  it  is 
not  so,  happily,  and  at  the  end  of  a  certain  time  a  sort  of  equilib- 
rium is  produced;  the  tie  becomes  suspended  above  the  ballast, 
when  it  is  not  submitted  to  any  load;  it  reposes  on  its  extremities, 
whatever  may  be  the  care  used  in  the  tamping,  and  inflects  in 
the  void  existing  between  the  upper  part  of  the  ballast  and  its 
lower  face,  a  void  which  arises  from  the  subsidence  of  the  support 
under  the  load.  This  observation,  which  I  have  made  many  times, 
and  which  is  of  great  importance,  as  we  shall  see  further  along, 
has  likewise  been  registered  by  Mr.  Couard  (paper  of  July,  1897, 
on  the  vertical  deformation  of  rails).  One  reads,  in  fact,  on  page 
36  of  this  interesting  article,  the  following  conclusion  of  the  causes 
of  the  vertical  deformation  of  rails.  "It  is  necessary  to  conclude 
that  the  ties  fixed  to  the  rail  rest  on  certain  points  suspended  above 
the  ballast,  and  that  right  at  the  rail  there  are  formed  under  the 
ties,  even  the  best  tamped,  depressions  in  the  ballast,  on  the  edges 
of  which  the  tie  is  supported;  under  the  passage  of  a  wheel  even 
lightly  loaded,  the  ties  make  contact  with  the  ballast  and  inflect 
to  the  bottom  of  the  depressions;  from  this  moment  only  the  increase 
of  the  bending  is  proportional  to  the  load." 

POSITION    OF   THE   TIE   IN    THE    TRACK. 

The  tie  thus  takes  an  appreciable  flexure,  which  produces  the 
dislocation  of  the  joint  and  the  deformation  of  the  rail,  and  this 
flexure  is  due,  in  the  ordinary  case,  to  its  excessive  length,  and  to 
the  unequal  distribution  of  the  pressure  on  the  ballast,  which  is 
a  consequence  of  it.  The  elasticity,  which  it  is  believed  should  be 
attributed  to  the  ballast,  and  which  is  so  construed  from  the  fact 
that  the  tie  returns  nearly  to  the  place  which  it  occupied  before 
the  passage  of  the  load,  depends  upon  the  bent  tie  itself  and  on 
the  reaction  of  the  roadbed.  It  is  possible  that  the  tie  does  not 
always  rest  on  its  extremities,  but  that  it  is  supported  on  its  central 


124  TRACK  DEFORMATIONS. 

part,  which  is  the  case  with  center  bound  ties;  that  is  to  say  with 
those  which  oscillate  about  their  center,  and  which  render  the  track 
unstable;  this  is  produced  when  the  tie  meets  a  resistance  at  its 
center  superior  to  that  at  its  extremities,  which  is  due  either  to  the 
inequalities  in  the  roadbed,  or  to  the  shocks  arising  from  the  ver- 
tical deformation  of  the  rails,  which  unwedge  the  tie  and  remove 
the  extremities  from  support. 

The  way  ballast  behaves  under  pressure  leads  to  consequences 
which  should  be  fully  understood,  and  which  explain  the  poor 
stability  of  certain  tracks.  Long  ties  have  often  been  preferred 
because  they  could  be  shifted  endwise  and  re-employed  after  adzing; 
that  is  a  very  bad  practice,  which  it  is  necessary  to  abandon  defi- 
nitely. The  ties  rest,  as  has  been  seen,  on  their  extremities;  the 
longest  by  reason  of  their  flexure  on  the  one  hand,  and  by  the  un- 
equal distribution  of  the  load  on  the  ballast  on  the  other  are  sit- 
uated at  a  higher  level  than  that  of  the  shorter  ties,  when,  after 
the  passage  of  vehicles,  they  have  returned  to  their  initial  posi- 
tion. For  the  compression  of  ballast  is  as  much  greater  as  the  point 
considered  is  brought  nearer  to  the  point  of  application  of  the  load, 
in  the  particular  case  of  the  rail.  This  explains  why  ties  of  un- 
equal length  succeeding  each  other  in  the  track  are  of  different 
heights,  and  produce  a  track  in  the  form  of  a  mountain,  with  high 
points  and  low  points.  The  track  becomes  jolty;  the  rails  present 
inequalities  prejudicial  to  their  good  stability,  and  that  effect  is  the 
more  sensible  the  greater  the  speed. 

But  the  same  principle  does  not  hold  with  ties  of  different  cross 
sections.  Under  the  load  they  descend  unequally  in  the  track,  but 
these  inequalities  should  be  restricted  in  comparison  with  the  first, 
because  the  longitudinal  deformation  of  the  tie  is  greater  than  its 
sinking.  From  a  long  tie  resting  suspended  on  its  extremities,  it 
follows  that,  in  the  experiments  which  we  have  made,  the  wood 
ties  ought  to  be  found,  after  the  passage  of  a  certain  number  of 
trains,  at  a  higher  level  than  that  of  the  composite  ties.  This  cir- 
cumstance, which  is  perfectly  explained,  has  nothing  mischievous 
in  it,  since  the  whole  track  is  displaced  parallel  to  itself.  But  in- 
equalities may  occur  at  the  passage  from  the  composite  ties  to  the 
ordinary  ties. 

EFFECT    OF    CLIMATIC    VARIATIONS    ON    THE   TIE. 

The  fact  that  the  ties  rest  on  the  end,  as  has  been  proved,  id 
also  confirmed  by  the  manner  in  which  they  behave  on  a  very  wet 
subsoil,  or,  on  the  contrary,  on  a  very  dry  support.  When  the  road- 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       125 

bed  is  argillaceous,  it  is  known  that  it  rapidly  becomes  muddy;  the 
water  is  arrested  on  its  surface  and  rises,  especially  in  the  central 
part,  with  the  mud  which  it  induces.  The  ballast  becomes  dirty, 
and  the  tie  pumps  because  it  rests  on  a  muddy  bed,  which  has, 
little  by  little,  replaced  the  ballast  buried  in  the  roadbed.  One  of 
the  methods  for  arresting  this  movement  and  this  pumping  con- 
sists in  the  establishment  of  walls  at  the  extremities  of  the  ties; 
the  central  part  of  the  track  is  thus  consolidated,  the  water  remains 
in  its  interior,  but  the  tie  no  longer  pumps,  because  it  is  carried 
on  a  firmer  soil,  and  because  it  no  longer  has  the  tendency  to  be 
supported  on  the  less  solid  part,  in  consequence  of  its  greater  flexure. 
This  method  amounts  to  diminishing  its  length  by  increasing  the 
points  of  support. 

In  the  same  way,  when  the  variations  of  temperature  are  pro- 
duced, the  loaded  tie  modifies  of  itself  its  bed.  When  the  ballast 
and  the  roadbed  are  very  wet  it  spreads  and  assumes  a  longer  bed; 
on  the  contrary,  when  the  support  becomes  dry,  the  tie  rises,  so 
to  speak,  above  its  original  axis.  It  takes  a  smaller  bed,  inferior 
to  that  which  its  length  would  permit. 

This  arises  from  the  manner  in  which  the  load  is  distributed 
over  a  given  surface,  and  the  fact  pointed  out  is  the  particular  ex- 
planation of  a  more  general  law.  The  zone  of  influence  of  a  load 
is  of  much  greater  extent,  as  the  surface  submitted  to  that  influ- 
ence is  more  capable  of  deformation.  It  is,  consequently,  of  small 
extent  when  the  support  is  rigid,  and  extends  further  when  the 
latter  is  flexible.  The  disadvantage  of  these  variations,  for  the  sub- 
ject which  now  occupies  us,  is  that  the  flexure  of  ties  increases 
with  the  deformation  of  the  support;  in  order  to  do  well  it  would 
then  be  necessary  to  eliminate  the  hygrometric  and  spongy  ballast, 
and  consolidate  the  roadbeds  susceptible  of  notable  deformation. 

Recapitulating,  it  can  be  said  that  the  tie,  such  as  actually  ex- 
ists, is  an  elastic  material  resting  on  a  support  subject  to  deforma- 
tion (the  ballast),  very  little  elastic  (the  roadbed).  Its  slight 
rigidity  causes  it  not  to  rest  on  its  whole  length,  and  to  distribute 
unequally  the  pressure  on  its  support,  the  parts  nearest  to  the  load 
being  submitted  to  a  severer  compression,  that  is  to  say,  to  a  greater 
deformation.  This  deformation  subsists  by  reason  of  the  feeble  elas- 
ticity of  the  roadbed,  and  at  the  end  of  a  short  time  the  tie  rests 
on  its  extremities;  it  is  a  well  understood  question  of  a  tie  well 
tamped  at  the  moment  of  laying,  and  established  upon  a  roadbed  of 
uniform  resistance. 


126  TRACK  DEFORMATIONS. 

TAMPING. 

Here  naturally  arises  the  problem  of  tamping  the  tie;  on  that 
question  engineers  are  divided,  because  they  have  not  perhaps  an- 
alyzed in  a  sufficient  manner  the  given  data  of  the  problem.  How 
many  times  have  I  heard  asked  of  the  heads  of  sections  the  length 
which  they  desired,  in  order  to  make  the  track  solid?  And  how 
many  different  replies  have  I  heard,  to  the  effect  that  the  problem 
appeared  unsolvable,  so  that  each  section  foreman  was  allowed  to 
make  his  own  rules! 

As  a  matter  of  fact,  this  does  not  make  any  trouble  under  actua] 
condition;  all  the  tamped  beds,  whatever  they  be,  lead  to  the  same 
result;  the  tie  always  rests  on  its  extremities.  It  is  necessary,  how- 
ever, to  guard  against  a  tamped  bed  over  the  whole  length  of  the 
tie,  because  it  might  cause  its  unwedging  and  make  it  center  bound. 

But  the  actual  situation  can  be  remedied,  and  in  a  general  man- 
ner; it  is  not  necessary  to  seek  the  length  of  the  tamped  bed  for 
a  tie  whatever  it  be,  that  is  to  say  the  length  of  its  bed  intended 
to  distribute  the  pressure  as  uniformly  as  possible  over  the  bal- 
last, and  to  prevent  consequently  its  deformation,  but — what  is  quite 
a  different  matter — the  length  of  the  tie  should  be  studied,  in  order 
that  it  may  undergo  the  least  flexure.  The  first  problem,  such  as 
is  proposed,  is  unsolvable;  the  second,  we  have  seen,  offers  a  very 
clear  and  very  precise  solution.  The  length  of  the  tie  of  least  flexure 
being  determined  by  experiment,  nothing  is  more  simple  than  to 
ascertain  the  best  length  for  the  tamped  bed.  Thus  it  has  been 
found  that  the  tie  ought  to  have  a  length  between  7.05  ft.  and 
7.22  ft.;  the  tamped  bed  will  have  a  total  length  equal  to  twice 
the  breech  of  the  tie.  The  whole  is  symmetrical  in  comparison 
with  the  load,  and  consequently  the  pressure  will  be  distributed 
nearly  uniformly  over  the  support.  It  would  be  mischievous  to 
extend  the  tamped  bed  on  the  side  of  the  center,  because  the  tie 
would  be  deformed  in  an  unequal  manner,  as  we  have  seen. 

LENGTH  OF  TIE  OF  LEAST  FLEXURE. 

An  objection  can  be  put  forth  against  the  shortening  of  the  tie 
on  account  of  the  obligation  to  avoid  the  cracks  which  are  produced 
at  the  extremities  in  consequence  of  the  introduction  of  the  screw 
spikes.  This  useless  length,  it  has  been  said,  is  a  necessary  evil; 
I  do  not  think  so,  for,  if  the  theory  of  the  tie  of  least  flexure  is 
admitted  as  exact,  nothing  prevents  consolidating  the  extremities 


METHODS  FOR  REMEDYING  TRACK  DEFORMATION.   127 

with  a  special  shoe,  or  a  screw  spike,  as  is  done  by  certain  French 
companies,  the  Eastern,  for  example. 

But  that  is  not  all,  and  if  it  is  desired  to  reduce  the  deforma- 
tion to  its  minimum,  which  is  necessary  in  order  to  allow  an  in- 
crease of  speed,  it  is  also  necessary  to  have  recourse  to  the  measure 
extolled  since  1897  by  Mr.  Coiiard.  That  is  to  say,  it  is  necessary 
to  give  to  the  tie  the  highest  possible  moment  of  resistance:  that 
of  the  wood  tie,  brought  to  the  standard  of  the  steel,  is  only  36, 
while  that  of  the  composite  tie  reaches  87,  and  is  never  less  than  60. 

The  experiments  which  we  have  made  naturally  condemn  all 
steel  ties  in  the  form  of  a  trough;  for,  on  the  one  hand,  their  resist- 
ing moment,  less  than  that  of  the  wood  ties,  is  too  weak,  and 
on  the  other  hand,  the  tamped  bed  is  almost  impossible  to  make, 
even  with  reduced  dimensions  which  would  lead  to  a  less  deforma- 
tion. The  moment  of  resistance  could  only  be  increased  in  two 
ways,  and  neither  is  practically  capable  of  realization;  it  would  b3 
necessary  either  to  increase  the  thickness  of  the  metal,  and  then  the 
tie,  already  too  costly,  would  have  a  prohibitive  price,  or  else  it 
would  be  necessary  to  increase  its  depth,  and  the  inconvenience  of 
a  bad  tamped  bed  would  be  still  more  noticeable.  Ties  in  the  form 
of  a  trough  should,  therefore,  be  abandoned,  and  their  general 
use  would  be  an  error,  which  would  be  regretted  in  the  future.  I 
am  not  referring  to  the  reduction  in  gage  of  the  track  produced 
in  consequence  of  the  permanent  flexure  by  the  tie,  nor  of  the  fast- 
enings, which  certainly  constitute  a  weak  point,  but  confine  myself 
simply  to  the  defect  of  rigidity  of  this  type,  and  to  the  difficulty 
of  tamping. 

The  reduction  of  the  flexure  of  ties  is  actually  a  necessity;  it 
will  correspond  also  to  a  reduction  in  the  longitudinal  movement, 
and  will  diminish  the  deformations  which  we  have  pointed  out. 
The  study  which  I  have  made  with  composite  ties  compared  with 
ordinary  ties  confirms  this  view.  The  transverse  flexure  is  dimin- 
ished at  the  same  time  as  the  longitudinal  movement,  which  pro- 
duces the  disorganization  of  the  splices.  These  facts  do  not  require 
explanation;  it  is  certain  that  the  increase  of  the  bending  moment 
ought  to  lead  to  a  less  deformation  of  the  track,  and  that  experi- 
ment has  confirmed  what  theory  has  presaged  for  a  long  time. 
It  has  also  been  possible  to  establish,  thanks  to  the  composite  tie, 
that  there  was  a  length  of  tie  of  which  the  deformation  was  min- 
imum, and  that  the  more  general  problem  of  the  zone  of  influence 
of  a  load  resting  across  a  support  on  a  material  capable  of  deforma- 
tion has  been  set  forth. 


•^    ^ 


'1 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       129 

COMPOSITE   TIES. 

The  experimental  composite  tie,  which  has  behaved  in  an  abso- 
lutely satisfactory  manner,  is  not  perhaps  the  only  model  of  this 
kind  which  could  be  conceived.  Made  with  a  metallic  skeleton, 
which  gives  to  it  a  great  rigidity,  which  is  to  be  desired,  contain- 
ing two  wooden  blocks,  on  which  the  fastening  is  made,  and  which 
distribute  the  pressure  on  the  roadbed,  it  presents  all  the  advant- 
ages which  one  could  wish:  rigidity  and  simplicity.  No  rivets,  no 
bolts;  the  compression  of  the  two  materials  is  obtained  by  clamp- 
ing the  skeleton  by  means  of  metallic  cross  bars.  It  is  true  that 
the  price  of  such  a  tie  is  high,  and  that  it  could  not  be  commonly 
employed;  on  tracks  of  much  traffic  this  objection  would  not  have 
great  value.  The  security  of  traffic,  the  economy  of  maintenance  by 
the  reduction  of  deformation  remain  to  be  put  in  the  balance  with  a 
higher  cost  price. 

But  one  of  the  inventors,  Mr.  Michel,  understood  how  well 
founded  this  objection  could  be  for  lines  of  less  frequent  traffic, 
and  has  designed  another  type  of  tie,  constituted  with  the  same 
materials,  wood  and  steel,  but  formed  of  more  simple  elements. 
The  metallic  parts  are  formed  of  two  pieces  of  channel  iron,  con- 
taining between  them  two  wooden  blocks  in  the  form  of  a  paral- 
lelepiped. The  assemblage  is  made  by  means  of  four  cross  bars 
per  block.  The  new  model  allows  the  realization  of  a  series  of  types 
of  resistance,  diverse  and,  consequently,  of  variable  pjice,  according 
to  the  resistance.  (Figs.  33,  34  and  35.) 

The  tie  thus  made  presents  the  same  advantages  as  the  first 
one  experimented  with,  rigidity  and  facility  for  compactness  of  the 
attachment,  but  it  does  not  rest  absolutely  on  the  same  principles. 
The  squeezing  was  obtained,  at  least  in  the  first  conception  of  the 
inventors,  by  the  rising  of  the  wedge;  in  this  case,  on  the  con- 
trary, it  becomes  perfect,  as  soon  as  the  beam  is  formed,  because 
the  cross  bars  make  the  elements,  wood  and  steel,  which  compose 
it,  act  jointly.  This  tie  is  not  open  to  the  charge  that  it  has  the 
grave  defect  of  comprising  a  great  number  of  pieces,  for  it  is  an 
armored  beam,  which  only  exists  after  the  assemblage  is  effectuated. 
It  would  be  possible  to  make  the  same  criticism  of  an  armored 
cement  beam,  or,  indeed,  even  against  a  compound  beam;  both  are 
created  only  when  their  elements  are  reunited.  The  tie  in  question 
is  definitely  an  armored  wooden  beam. 

The  assemblage  can  be  made  with  the  perfection  and  solidity 
which  it  is  proposed  to  have  for  it,  as  was  shown  in  experiments 


130  TRACK  DEFORMATIONS. 

undertaken  at  the  laboratory  of  the  Ecole  des  Fonts  et  Chaussees. 
The  tie  submitted  to  the  test  was  composed  of  two  pieces  of  channel 
iron,  5.51  in.  deep,  0.20  in.  thickness  of  web  and  11.42  in.  width 
of  flange,  bound  together  with  cross  bars  of  2.36  in.  by  3.94  in. 
Each  of  the  oak  blocks  creosoted,  at  least  superficially,  was  27.56  in. 
long,  5.51  in.  deep  and  8.27  in.  wide.  The  assemblage  of  the  ele- 
ments was  made  by  placing  the  girdle  constituted  of  channel  iron 
against  the  wood,  and  by  introducing  the  cross  bars  between  the 
flanges  of  the  channels  by  force.  This  procedure  of  squeezing  was 
primitive,  since  it  was  arranged  only  by  primitive  means. 

Nevertheless,  it  was  sufficient,  since  the  sliding  of  the  piece  of 
wood  along  the  metallic  body  required  a  force  of  8.8  net  tons.  The 
pressure  obtained  under  the  action  of  four  clamps  being  13.2  net 
tons,  the  coefficient  of  friction  of  wood  against  the  iron  was  0.3. 
The  dislocation  of  such  a  beam  is  therefore  not  to  be  feared,  and  it 
is  well  to  remark  that  under  a  similar  force  the  wood  tie  would 
be  either  broken  or  near  breaking,  and  that  the  steel  tie  would  be 
on  the  point  of  bending  (flexure  of  0.91  in.). 

But  the  assemblage  can  be  assured  by  a  methodical  and  even 
pressure,  and  the  above  limit  may  be  exceeded,  if  necessary.  The 
pieces  to  be  united  will  be  placed  under  a  press  and  the  heated  cross 
bars  will  be  introduced  between  the  flanges  of  the  channels;  there  will 
thus  be  realized,  if  it  is  desired,  a  total  pressure  of  39.6  net  tons, 
which  supposes  a  tension  of  9.9  net  tons  per  cross  »bar.  Each  of 
them  having  a  section  of  0.93  sq.  in.  would  not  be  stressed  to  more 
than  21,334  Ibs.  per  sq.  in.,  which  is  acceptable.  As  to  the  wood, 
it  would  only  be  stressed  to  526  Ibs.  per  sq.  in.,  about  one-tenth  of 
the  breaking  load. 

It  may  be  asked  if  the  pressure,  being  obtained,  will  be  main- 
tained in  spite  of-  the  effects  of  variations  of  temperature.  I  can- 
not cite  experiments  with  figures  for  support;  however,  I  will  cite 
the  first  ties,  which,  placed  in  the  track  for  four  years,  and  sub- 
mitted in  consequence  to  all  the  temperature  changes,  have  be- 
haved well  with  a  total  pressure  less  than  that  which  has  since 
been  realized.  No  yielding  has  been  produced,  and  the  central  wedge 
could  never  be  raised,  except  for  a  few  millimeters.  The  proof 
has  then  been  made  experimentally  that  yielding  is  not  possible 
under  the  conditions  of  ,test;  but  I  do  not  wish  to  limit  myself  to 
this  demonstration,  and  I  am  having  executed  at  this  moment  a 
set  of  experiments  relative  to  the  effect  of  temperature  variations 
on  the  clamping  of  beams  made  like  the  ties. 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       131 

There  is  another  point  which  I  am  having  studied  at  the  same 
time,  and  which  deserves  special  mention.  It  is  the  hardening  of 
the  material  by  the  effect  of  compression,  a  hardening  which  will 
diminish  the  sinking  of  the  rail  in  its  support,  and  consequently 
the  deformation  of  the  track  and  the  stress  on  the  fastenings.  It 
is  a  general  law;  the  compression  of  the  material  gives  a  resist- 
ance to  it  which  it  has  not  in  a  natural  state.  Mr.  Considere,  in 
a  note  inserted  in  the  Annales  des  Fonts  et  Ghaussees  (second  quar- 
ter of  1904),  has  shown  that  the  resistance  of  cement  was  increased 
in  the  proportion  of  1  to  6.  The  same  fact  should  exist  with  wood; 
it  is  fitting  to  establish  it,  and  to  show  every  advantage  which  can 
be  derived  from  it.  It  is  probable  that,  thanks  to  this  hardening, 
the  fastenings  will  present  a  greater  resistance  and  that  they  can 
be  submitted  to  greater  forces. 

The  best  wood,  whether  for  ordinary  ties  or  of  blocks  for  com- 
posite ties,  is  heart  oak.  It  is  not  necessary  to  creosote  it;  it  is 
sufficient  to  use  a  coat  of  tar  and  lime  to  protect  its  upper  face 
from  the  action  of  inclement  weather.  The  experiment  made  on  the 
tracks  on  the  line  from  Mouchard  to  Bourg  produced  excellent  re- 
sults; it  demonstrated  that  this  treatment  was  successful  in  main- 
taining ties  which  would  have  been  rejected  with  brief  delay  with- 
out the  preservative.  The  latter  does  not  prevent,  at  the  end  or  on 
the  sides,  the  slow  and  progressive  seasoning  of  the  tie. 

The  tie  may  also  be  seasoned  by  floating  it  for  five  or  six  months 
to  eliminate  elements  of  decay,  but  this  process  is  long,  and  not 
very  practicable  because  of  the  long  drying  subsequently  required. 
If  the  oak  contains  sap,  which  is  unfortunately  very  common,  the 
floating  can  s^rve  to  preserve  the  beam;  but  creosoting  is  a  disad- 
vantage rather  than  an  advantage.  The  sap  alone  absorbs  the, creo- 
sote in  a  sensible  manner,  and  after  the  injection  forms  an  impene- 
trable envelope,  under  the  protection  of  which  the  sap,  not  being 
able  to  evaporate,  enters  into  fermentation  and  attacks  the  wood. 
It  is  undoubtedly  better  not  to  creosote  sap  oak.  - 

,:     The  same  thing  does  not  hold  true  for  pine,  spruce  or  beech. 
These  woods  season  rapidly  and  are  capable  of  absorbing  a  quantity 

^t 

of  creosote  sufficient  to  render  antiseptic  the  small  amount  of  sap 
which  still  remains  after  seasoning  (about  20-  per  cent.).  But  it 
is  necessary  to  creosote  to  refusal,  which  requires  the  employment 
o-f  at  least  55  Ibs.  of  antiseptic  liquid  for  a  tie  of  8.53  ft.;  under, 
these  conditions  the  sap  is,  so  to  speak,  surrounded  by  creosote, 
and  any  fermentation  is  impossible.  With  a  smaller  dose,  the  sap; 


132  TRACK  DEFORMATIONS. 

not  being  given  immunity,  enters  into  fermentation,  and  decay  com- 
mences; this  has  been  observed  when  the  amount  of  creosote  is 
reduced  to  35^  Ibs. 

Besides  these  methods  of  preservation  of  ties,  attention  should 
be  directed  to  the  covering  of  their  upper  part  by  ballast,  the  em- 
ployment of  plates  which  protect  the  seat  of  the  fastenings,  and 
consequently  the  fastenings  themselves.  Perhaps  it  would  be  well, 
in  the  case  of  secondary  companies,  where  the  ties  often  perish  by 
the  fastenings  and  the  decay  of  their  sockets,  to  place  in  default 
of  a  plate,  a  hoop-iron  shim,  whose  only  purpose  would  be  to  cover 
the  seat  of  the  fastenings.  On  the  P.  L.  M.,  notably,  where  a  plate 
is  employed,  the  decay  of  ties  is  scarcely  produced,  except  in  the 
central  part  The  fastenings  are  still  good,  except  when  they  have 
undergone  excessive  turning,  and  then  the  tie  ought  to  be  rejected. 
This  is  not  true  on  lines  where  the  rail  rests  directly  on  the  tie, 
and  where  the  fastenings  are  absolutely  uncovered;  rust  attacks 
the  screw  spike  and  the  wood  which  surrounds  it.  The  fastening 
becomes  bad  before  the  tie  has  become  unfit  for  usage.  From  that 
arises  the  necessity  for  having  recourse  to  a  method  for  consolida- 
tion of  the  fastenings,  which  is  not  generally  necessary  on  tracks 
provided  with  plates.  It  is  the  same  in  the  case  of  the  ties  laid 
with  even  joints,  for  those  of  the  following  end,  notably,  often 
perish  at  their  fastenings  by  reason  of  the  hammering  which  they 
support  at  the  joint.  The  wood  in  which  the  screw  spike  is  en- 
gaged is  torn,  and  the  piece  should  be  rejected.  It  holds  that  at 
the  end  of  a  certain  time  this  piece  is  left  in  the  air;  the  fasten- 
ings support  the  weight  of  the  beam  and  finish  by  tearing  the  wood 

METHODS  OF  IMPROVING  THE   JOINT. 

The  obligation  of  obtaining  a  more  rigid  track,  in  view  of  real- 
izing greater  speeds,  and  also  of  reducing  expenses  of  operation, 
is  in  contradiction  to  the  well-known  principle  that  a  railroad  track 
should  be  elastic,  and  should  not  present  hard  spots.  It  is  neces- 
sary, in  discussing  this  question,  to  define  the  word  "elasticity,"  as 
employed  in  this  case.  Is  an  elastic  track  that  which,  under  the 
effect  of  loads,  returns  each  time  to  its  original  position?  Or  should 
elasticity  be  understood  as  a  special  quality,  difficult  to  define,  which 
produces  smooth  rolling;  should  the  track  be  like  a  spring  of  great 
power,  slowly  registering  the  shocks  and  diminishing  the  effect  so 
disastrous  for  vehicles  and  for  travelers? 

If  the  first  sense  is  adopted,  an  elastic  track  is  necessarily  a 
bad  track;  it  does  not  diminish  the  shocks,  it  multiplies  them.  For 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       133 

it  is  impossible  that  this  elasticity  should  be  at  all  points  of  like 
proportions;  here  the  track,  under  the  effect  of  the  ballast,  of  the 
roadbed,  and  other  causes,  will  be  deformed  more  than  at  the  neigh- 
boring point.  Shocks  and  jolts,  impossible  to  avoid,  will  result  from 
it.  Under  existing  conditions,  with  ties  as  they  are  laid,  having 
small  rigidity,  it  may  be  said  that  on  each  rail  length  there  is  first 
a  drop,  extending  to  the  middle  of  the  section;  then  a  rise,  from 
this  point  to  the  end  of  the  rail.  Both  in  the  drop  and  in  the  rise 
there  are  high  points  and  low  points,  which  exaggerate  the  general 
bad  effect.  This  is  occasioned  by  the  fact  that  the  joint,  in  conse- 
quence of  the  drawing  together  of  the  ties  at  the  splicing,  which 
stiffens  the  rail,  is  the  least  elastic  point  of  the  track,  and  that  in 
reality  a  hard  point  has  been  obtained  when  the  contrary  result 
was  sought. 

For,  up  to  the  present  time,  if  we  have  used  a  suspended  joint, 
it  is  because  we  have  been  afraid  of  having  a  hard  point  in  its 
place;  it  has  been  surmised,  wrongfully,  that  the  supported  joint 
was  bad,  and  that  it  was  necessary  to  keep  it  in  the  air  in  order 
to  preserve  that  elasticity,  which  is  only  a  deception.  A  track 
absolutely  rigid  as  a  marble  table  would  be  infinitely  preferable 
for  rolling  to  a  track  capable  of  deformation,  like  that  which  we 
actually  have.  This  deformation— for  the  word  "elasticity"  is  im- 
proper— is  a  necessity;  it  cannot  be  made  otherwise,  but  it  is  not 
an  advantage,  any  more  than  one  could  pretend  that  the  elasticity 
of  the  bridge  of  Saints-Peres  was  sought  for,  and  constitutes  progress. 

It  has  been  forgotten  that,  on  a  track  as  actually  constructed, 
hard  points  were  not  .possible,  because  all  the  points  of  this  track 
become  deformed,  and  because,  under  the  ties,  the  vertical  dis- 
placement is  greater  than  anywhere  else.  Mr.  Coiiard  has  shown 
that  the  flexure  of  rail  between  two  consecutive  ties  was  comprised 
between  one-tenth  and  one-twentieth  of  a  millimeter,  and  that  the 
lowering  of  a  tie  under  a  load  can  reach  four  millimeters  (0.16  in.); 
the  mean  is  two  millimeters  (0.08  in.),  that  is  to  say  the  flexure 
of  the  rail  is  comprised  between  1/200  and  1/400  of  the  lowering 
of  the  tie,  and  can  be  considered  as  infinitely  small  in  comparison 
with  the  latter.  Otherwise  put,  the  tie  bends  infinitely  more  than 
any  other  point  of  the  track;  it  is  therefore  wrong  to  think  that  it 
can  constitute  a  hard  point. 

The  necessity  for  laying  rails  in  short  lengths,  in  order  to  leave 
play  between  them  for  expansion,  should  not  allow  this  fact  to  be 
lost  sight  of,  that  the  extremity  of  a  rail  is  like  any  other  point, 


134  TRACK  DEFORMATIONS. 

and  that  it  should  not  be  otherwise  treated.  Now  the  two  extremi- 
ties of  the  rails  which  follow  each  other  have  a  marked  tendency 
to  vibrate  differently;  and  from  this  tendency  a  fall  Is  created, 
which  goes  on  increasing  with  time. 

Not  only  is  the  splicing  displaced,  but  the  rail  is  curved  under 
the  effect  of  the  fall  and  of  the  shock  which  follows.  Mr.  Couard 
has  shown  that  the  unequal  level,  between  the  middle  of  the  rail 
and  its  extremities,  can  attain  0.8  in.,  divided  thus: 

Permanent  bending  between  the  middle  and  the  extremity  of  the  rail.  .0.56  in. 

Variable  flexure   0.12  " 

Compression  of  the  ballast  and  of  the  subsoil 0.12  " 


Total    0.80  in. 

This  material  inequality  is  due  to  the  fall  and  to  the  shock, 
that  is  to  say,  to  the  suspended  joint;  it  is  the  direct  consequence 
of  it.  When  laying  rails  an  allowance  of  0.02  in.  at  the  extremi- 
ties is  admitted;  if  this  allowance  is  in  a  contrary  direction  at 
the  two  extremities  of  adjacent  rails,  it  is  possible  for  the  total 
drop  to  amount  to  0.04  in.  This  circumstance,  which  is  frequently 
presented,  is  the  cause  for  the  permanent  bending,  which  rises  even 
to  0.56  in.  The  hammering  of  the  rail  at  its  extremities  aggravates 
the  original  situation  up  to  the  limit  indicated.  It  is  the  same  as 
far  as  the  variable  flexure  is  concerned;  an  end  of  rail  of  about 
11.81  in.,  since  the  ties  of  the  even  joint  are  spaced  about  23.62  in., 
should  not  bend  under  the  loads  to  which  it  is  submitted  by  more 
than  one-tenth  of  a  millimeter.  The  variable  bending  which  it  takes. 
and  which  is  0.12  in.,  is  solely  due  to  the  shock,  and,  consequently, 
to  the  suspended  joint.  It  is  possible  then  to  reduce  in  an  appre- 
ciable manner  the  unequal  level  of  0.67  in.  by  holding  the  joint 
and  preventing  it  from  vibrating.  We  will  then  have  only  the 
flexure  of  the  tie,  the  compression  of  the  roadbed,  which  can  be 
reduced  to  0.06  in.  That  is  to  say,  by  sustaining  the  joint  the  un- 
equal level  which  is  actually  produced  can  be  reduced  to  one-twelfth 
of  its  real  value.  This  will  not  only  make  better  track,  since  the 
shock  will  be  lessened,  but  it  will  prolong  the  life  of  the  rail,  occa- 
sioning a  material  economy  in  renewals. 

The  disorganization  of  the  splicing,  which  is  the  first  effect  of 
the  play  allowed  at  the  extremities  of  the  rails,  their  curvature 
and  the  shock  which  follows,  can  be  avoided  by  fixing  the  ends  on 
a  very  rigid  tie.  It  is  conceivable  that  the  two  extremities,  fast- 
ened on  a  single  piece  would  act  jointly  with  that  piece,  and  would 
not  have  the  tendency  to  work  separately,  as  actually  takes  place. 
It  is  naturally  necessary  that  the  tie  be  rigid  in  order  to  avoid 


METHODS  FOR  REMEDYING  TRACK  DEFORMATION.   135 

the  stress  on  the  fastenings,  but,  under  that  reservation,  the  method 
which  we  have  outlined,  and  which  is  very  old,  only  presents 
advantages. 

Mr.  Coiiard,  in  his  study  on  the  vertical  deformation  of  rails, 
makes  the  following  comment: 

"The  principal  attempts  which  have  been  made  at  reinforcing 
the  splices  of  rails  and  the  want  of  success  of  the  oldest  attempts, 
leaves  little  to  be  hoped  for  from  the  new,  and  I  do  not  believe  that 
it  will  be  in  this  direction  that  the  solution  of  the  stability  of  the 
joint  will  be  found. 

"Experience  proves  that  it  is  dangerous  to  suppress  the  allow- 
ance for  expansion  in  railroad  tracks. 

"The  unsymmetrical  placing  of  ties  in  such  a  way  that  there 
is  a  greater  number  under  the  first  half  of  the  rail,  appears  to 
have  given  good  results  on  the  line  from  Saint-Etienne  to  Lyons, 
the  busiest  of  the  P.  L.  M.  system. 

"The  reinforcement  of  the  joint,  by  drawing  together  the  ties 
of  the  even  joint,  has  been  well  tried;  several  companies  have  also 
sought  to  bring  the  ties  of  the  even  joint  still  nearer  together,  in 
connection  with  the  suspended  joint." 

This  tendency  to  draw  nearer  and  nearer  together  the  ties  of 
the  even  joint  leads  to  the  adoption  of  the  supported  joint;  it  is 
therefore  not  astonishing  to  find  in  the  discussion  at  the  Congress  of 
1895  at  London  the  following  declaration  by  Mr.  John  M.  Toucey, 
of  the  New  York  Central: 

"We  have  no  more  suspended  joints  since  we  tried  them  some 
years  ago.  We  abandoned  them  because  the  inflection  was  too  great. 
The  joint  is  supported  by  three  ties:  one  in  the  middle,  the  others 
at  the  extremities  of  the  splices. 

"With  the  rails  of  100  Ibs.  per  yard  and  this  splice  bearing 
on  three  ties,  there  is  scarcely  any  sensible  inflection  at  the  joint. 
The  rolling  is  almost  as  smooth  in  the  middle  of  the  rail  as  at  the 
extremities.  We  believe,  therefore,  that  our  system  of  splicing  is 
the  best." 

I  concur  in  this  rational  conclusion.  Mr.  Coiiard  also  recog- 
nizes that  this  is  good  practice,  and  he  has  shown  that  if  the  sup- 
ported joint  has  been  rated  as  bad,  it  is  because  the  tie  at  the  joint, 
induced  successively  by  the  rail  in  advance  and  by  the  following- 
rail,  oscillated  and  easily  became  untamped  when  adjacent  ties  were 
Sl1/^  in.  away.  He  has  established,  in  fact,  that  in  the  tunnels  of 
Blaisy-Bas  and  of  Saint-Irenee,  with  spacing  reduced  to  23.62  in., 


136  TRACK  DEFORMATIONS. 

and  with  87-lb.  rails,  the  supported  joints  behaved  well,  although 
the  pivoting  of  the  ties  still  existed. 

I  conclude,  then,  that  the  only  practical  method  for  improving 
the  joint  is  to  support  it  on  a  tie  and  to  place  two  others  11.81  in. 
from  it.  Moreover,  untamping  will  be  much  less  to  be  feared  if  a 
rigid  type  of  tie  is  adopted,  which  always  rests  on  its  appointed 
bed.  Experiment  will  alone  permit  of  pronouncing  upon  this  sub- 
ject; but  it  can  be  said  that  untamping  will  then  be  less  easy, 
because  the  tie,  resting  on  nearly  a  plane  surface,  will  distribute 
the  pressure  on  the  ballast  uniformly,  while  actually,  by  reason  of 
the  flexure,  the  pressure  is  distributed  unequally,  and  the  ballast 
deformed  unequally,  which  produces  unwedging. 

But  this  measure  will  only  be  useful  after  we  succeed  in  cor- 
recting the  unevenness  which  exists  between  the  two  extremities 
of  the  rail,  and  which  proceeds,  on  the  one  hand,  from  defects  in 
manufacture,  and,  on  the  other,  from  defects  in  laying.  It  is  under- 
stood that  if  the  joint  still  presents,  after  establishment  of  the 
track,  any  unevenness,  in  whatever  direction,  the  latter  will  become 
rapidly  worse,  the  tie  of  the  joint  becoming  unwedged  and  finish- 
ing by  churning,  which  is  actually  the  case  with  the  even  joint. 
The  unevenness  will  increase,  and  the  state  of  things  will  become 
just  what  it  is  now.  The  first  measure  to  be  taken  consists,  then, 
in  suppressing  the  existing  unevenness;  it  is  possible  to  accomplish 
this  in  two  ways,  either  by  placing  wedges  under  the  lowest  part 
of  the  rail  (but  this  would  be  difficult,  for  it  is  a  question  of  some 
tenths  of  millimeters),  or  by  planing  the  "two  extremities  of  the 
rail  with  a  portable  tool,  which  seems  easy,  in  order  to  place  the 
rolling  surface  at  the  same  level  on  both  sides  of  the  joint. 

Consolidation  of  the  fastenings  is  indispensable  to  complete  the 
good  support  of  the  joint.  If  it  is  indispensable  to  improve  the 
joint,  which  is  certainly  the  weakest  point  in  the  track,  it  is  no 
less  necessary  to  pay  attention  to  the  holding  power  of  the  fasten- 
ings. It  has  been  seen  how  important  they  were,  as  much  from 
the  point  of  view  of  assuring  the  joint  action  between  the  rail  and 
the  tie  as  of  the  resistance  opposed  to  lateral  movement. 

As  far  as  concerns  this  resistance,  it  is  proper  to  utilize^  the 
whole  surface  of  the  head  of  the  screw  spike,  and,  on  that 
account,  to  adopt  the  tie  plates,  which  diminish  the  effect  of  the 
cutting  which  the  rail  exercises  on  the  body  of  the  screw  spike. 
Certain  railroad  companies,  fearing  this  cutting,  have  kept  its  shank 
away  from  the  edge  of  the  base  of  the  rail;  this  is  a  bad  solution, 
for,  if  it  serves  to  avoid  one  difficulty,  it  brings  about  another  equally 


METHODS  FOR  REMEDYING  TRACK  INFORMATION.   137 

serious.  Lateral  displacement  of  the  rail,  since  it  is  not  well  sup- 
ported and  its  overturning  on  curves,  or.  sliding,  is  not  properly 
guarded  against.  Experiments  made  on  the  P.  L.  M.  on  this  sub- 
ject show  that  with  a  metallic  plate  the  cutting  is  very  much  dimin- 
ished; it  is  true  that  we  must  take  care  of  the  abnormal  wear 
which  is  necessarily  produced  between  two  metallic  surfaces,  the 
lower  part  of  the  base  and  the  upper  surface  of  the  plate.  JBut  it 
is  possible  to  interpose  between  the  two  surfaces  a  plate  of  felt  or 
poplar. 

On  this  account  the  reinforcement  of  the  plates  actually  in  use 
on  the  P.  L.  M.  was  occasioned;  it  has  been  seen,  in  the  first  part 
of  this  study,  that,  for  want  of  a  suitable  reinforcement,  the  screw 
spike  is  not  sufficiently  sustained,  and  that  under  the  influence  of 
a  relatively  weak  push  exercised  on  the  rail,  it  has  a  tendency  to 
be  overturned,  not  being  stopped  by  the  plate.  The  reinforcement, 
which  we  have  made  practical,  has,  on  the  contrary,  arrested  the 
movement  of  overturning  and  diminished  the  chances  for  inclina- 
tion of  the  rail,  and,  consequently,  of  the  spreading  of  the  track. 
One  can  object,  and  it  is  probably  the  reason  for.  maintenance  of 
the  actual  type,  that  the  reinforcement  of  the  plate  can  induce  loosen- 
ing from  the  base  of  the  rail,  the  head  of  the  screw  spike  con- 
tinuing to  be  supported  on  the  reinforced  part  of  the  plate,  while 
no  longer  being  applied  to  the  base.  It  does  not  seem  impossible 
to  remedy  this  disadvantage;  it  suffices,  in  fact,  to  slide  an  iron 
wedge  under  the  head  of  the  screw  spike,  in  the  same  manner  that 
wedges  are  placed  between  the  splice  and  the  lower  part  of  the 
head  of  the  rail.  The  importance  of  the  result  to  be  obtained 
justifies  the  measure  which  should  be  taken. 

EMPLOYMENT    OF    THE    TREENAIL. 

As  a  means  of  consolidation  of  the  fastenings,  above  all  of  those 
which  are  used  in  ties  already  old,  the  treenail  has  been  employed 
with  success.  The  wooden  treenail,  Collet  system,  was  at  first  put 
in  service,  then  the  metallic  treenail,  of  which  one  of  the  best  types 
is  the  one  invented  by  Mr.  Thiollier.  We  pointed  out,  in  the  first 
part  of  the  study,  the  results  which  the  Collet  treenail  gave.  I 
think  it  proper  to  recall  them  in  revision. 

The  resistence  to  excessive  turning,  which  is  an  essential  quality 
of  the  fastening  is: 

For  pine  without  treenail 132  Ibs. 

For  pine  with  treenail   176    " 

For  hardwood,  oak  or  beech,  without  treenail 220    " 

\        For  hardwood,  oak  or  beech,  with  treenail   .  .  .  242    " 


138  TRACK  DEFORMATIONS. 

The  resistance  to  tearing  out,  which  is  about  11,023  Ibs.,  in 
creosoted  pine  with  the  treenail,  in  place  of  7,716  Ibs.,  seems  to  de- 
crease with  time;  for  it  decreases  at  the  end  of  two  years  to  8,818 
lb.3.,  to  a  limit  sensibly  equal  to  that  which  the  wood  possesses  in  its 
natural  state.  That  holds  according  to  the  manner  even  in  which 
the  treenail  is  made;  the  latter  is,  in  fact,  cut  out  of  wood  in  the 
direction  of  the  grain,  and  thoroughly  creosoted.  Now  it  is  known 
that  a  piece  of  wood  thus  established  is  in  bad  condition  for  receiv- 
ing spikes  or  screws;  they  both  hold  badly.  The  wood  does  not 
permit  of  penetration  by  a  screw  thread;  this  has  been  proved  by 
experiment  with  the  treenail.  Thus,  when  the  insertion  is  first 
made,  the  force  of  extraction  is  exercised  on  the  treenail;  at  the 
end  of  a  few  months  the  combination  of  screw  spike  and  tree- 
nail submitted  to  extraction  acts  otherwise,  it  is  the  screw  spike 
which  is  withdrawn,  under  a  force  of  about  7,716  Ibs.  It  holds 
from  this  that  the  wood  of  the  treenail  has  not  received  the  im- 
print of  the  screw  thread;  it  is  simply  compressed  more  or  less 
strongly,  which  in  the  beginning  assures  the  union  of  the  two  pieces. 
But  at  the  end  of  a  short  time  the  effect  of  this  compression  dimin- 
ishes, the  wood  shrinks  little  by  little,  the  contact  diminishes,  and 
the  force  which  is  necessary  for  extracting  the  system  diminishes. 

The  resistance  to  tearing  out  in  new  oak  ties  is  about  13,228  Ibs.; 
it  is  about  15,432  lb*s.  when  the  latter  are  provided  with  treenails. 
But  there  is  equally  produced  a  diminution  of  resistance  with  time, 
as  much  in  the  first  case  as  in  the  second,  and  the  reason  for  it  is 
the  same. 

As  far  as  the  resistance  to  overturning  is  concerned,  the  em- 
ployment of  the  treenail  does  not  appear  to  increase  it  materially; 
it  depends,  above  all,  as  has  been  seen,  on  the  reinforcement  of  the 
plate. 

The  useful  effect  of  the  treenail  is  not,  in  fact,  very  great  for 
opposing  such  a  movement,  because  the  upright  wood  of  the  tree- 
nail presents  quite  a  weak  resistance,  scarcely  the  tenth  of  the  re- 
sistance of  the  wood  submitted  to  a  force  perpendicular  with  its 
fibers;  because,  under  the  influence  of  the  force,  the  hole  takes  an 
oval  shape,  and  because  the  wood  crushes. 

Another  disadvantage  in  this  method  of  consolidation  of  the 
fastenings  arises  from  the  fact  that  its  employment  requires  the 
use  of  plates,  in  order  to  protect  its  upper  surface.  It  is  thus  that 
the  treenails  of  ties  on  tracks  of  the  P.  L.  M.  Co.  are  well  preserved, 
because  they  are  provided  with  a  plate,  but  they  shrink  in  the 
same  ties  without  the  plate,  and  a  space  between  the  treenail  and 


METHODS   FOR  REMEDYING  TRACK  DEFORMATION.       139 

the  wood  of  the  tie  is  produced,  rendering  the  fastening  bad  and 
very  shaky.  This  fact  explains  why,  with  certain  companies  where 
the  plate  is  not  in  use,  the  wooden  treenail  could  not  be  employed. 
It  is  possible,  we  believe,  to  remedy  this  disadvantage  by  placing 
en  the  head  of  the  treenail  a  protecting  coat  composed  of  tar  and 
sand,  or  of  lime,  sufficiently  elastic  to  lend  itself  to  all  the  move- 
ments of  the  tie. 

It  may  therefore  be  said  that,  under  actual  conditions,  the  tree- 
nail prolongs  the  durability  of  a  tie  whose  fastenings  are  damaged, 
but  it  does  not  give  an  increase  of  resistance,  since  the  latter  dimin- 
ishes quite  rapidly.  It  is  not  safe,  therefore,  to  count  on  its  em- 
ployment for  improving  the  fastenings  in  a  permanent  manner; 
at  the  beginning  an  improvement  is  obtained,  but  it  does  not  seem 
to  continue. 

THIOLLIEB   TREENAIL. 

Against  excessive  turning,  which  it  is  important  to  avoid,  there 
is  net  any  increase  of  resistance;  the  employment  of  the  Thiollier 
metallic  treenail  seems  on  the  contrary  to  produce  this  increase. 
This  treenail  is  nothing  but  a  steel  helix  of  oval  section,  of  which 
the  number  of  spirals  varies  according  to  the  pitch  of  the  screw 
spike,  and  which  is  incorporated  right  at  each  screw  spike  of  the 
tie  in  a  socket  previously  cut  in  the  tie  by  means  of  a  cutting  tap. 
The  lining  has  the  same  pitch  as  the  screw  spike  to  be  employed, 
and  an  interior  diameter  about  the  same  as  that  of  the  core  of  the 
screw  spike,  in  order  to  reduce  the  play  between  the  two  pieces  to 
the  minimum;  the  helix,  prepared  for  its  normal  service,  is  always 
flush  with  the  upper  part  of  the  tie,  lines  the  place  cut  out  for  the 
plate,  and,  at  its  lower  part,  ought  always  to  rest  on  at  least  0.39  in. 
of  wood  not  tapped. 

According  to  the  inventor,  as  soon  as  the  squeezing  force  com- 
mences, by  the  contact  of  the  cap  of  the  screw  spike  with  the  rail 
or  the  chair,  the  lining  increases  in  diameter,  embraces  the  forms 
of  the  screw  spike,  which  places  the  latter  under  protection  against 
all  spontaneous  untightening,  and  assumes  the  function  of  a  spring, 
all  the  different  spirals  obeying  the  force  parallel  to  its  axis  trans- 
mitted by  the  screw  spike. 

The  lining,  by  its  diameter  greater  than  that  of  the  screw, 
engages  the  parts  of  the  wood  with  a  more  extended  surface  than 
that  engaged  by  the  threads  of  the  screw  spike,  and  in  re-employed 
ties,  where  the  same  site  is  preserved  for  the  screw  spike,  the  parts 
of  the  wood  less  altered  or  less  blackened. 


140  TRACK  DEFORMATIONS. 

These  advantages  have  caused  certain  railroad  companies  to 
employ  the  Thiollier  lining.  The  results  of  extraction  are  essen- 
tially the  same  as  those  which  are  obtained  with  the  Collet  treenail; 
that  is  to  say,  the  resistance  is  increased  by  about  30  per  cent.  But 
experience  has  not  perhaps  been  sufficient  to  enable  us  to  pro- 
nounce on  the  efficiency  of  the  lining  after  a  certain  time  of  em- 
ployment; and  it  is  to  be  feared  that  there  will  be  produced,  as  with 
the  Collet  treenail,  a  certain  relaxation  of  the  distended  fibers. 
In  each  case  the  resistance  to  excessive  turning  is  limited.  It  does 
not  increase  constantly,  as  a  purely  superficial  examination  would 
tend  to  prove.  It  is  necessary  to  guard  against  squeezing  it  too 
tightly,  for  the  spiral  and  the  screw  spike  are  made  like  a  nut 
and  its  bolt.  In  acting  on  the  bolt,  the  nut  is  made  to  ascend; 
the  spiral  ascends,  the  rings  come  to  be  pressed  against  each  other 
and  against  the  plate,  tearing  the  fibers  of  the  tie,  and  the  apparent 
resistance  to  excessive  turning  is  as  much  greater  as  the  fastening 
is  more  dislocated.  But  it  is  easy  not  to  reach  this  limit,  and  it 
is  easily  possible  to  remedy  this  disadvantage  by  providing  the  tree- 
nail with  a  spur  applied  against  the  bottom  of  the  tie,  and  by  dimin- 
ishing the  flexibility  of  the  spirals  in  order  that  they  may  not  be 
able  to  be  pressed  against  each  other. 

Nevertheless,  the  Thiollier  lining  is  an  excellent  palliative,  for 
it  increases  the  resistance  to  transverse  overturning  comparatively 
with  the  known  systems,  and  is  economical,  since  the  lining  can 
be  placed  without  withdrawing  the  tie  from  the  track,  which  pro- 
duces an  economy  of  about  1  franc  (19.4  cents). 

Apart  from  the  effect  of  overturning,  which  is  very  rarely  pro- 
duced, while  admitting  at  the  same  time  that  it  can  take  place, 
there  is  occasion  for  considering  the  resistance  which  the  rail,  pro- 
vided with  its  plate  and  its  fastenings,  presents  to  sliding.  It  has 
been  possible  to  verify  this  resistance  by  means  of  the  Collet  decli- 
metre,  and  by  a  special  arrangement  which  permits  of  direct  action 
on  the  plates.  The  results  of  these  experiments  are  given  below: 

I'ine  ties  creosoted  :     With  bare  screw  spikes 8,598  ibs. 

With  screw  spikes  and  treenails 11,905    " 

With  screw  spikes  provided  with  Thiollier  linings 15,212    " 

New  oak  creosoted  cross-ties  with  bare  screw  spikes 17,637    " 

New  beech  creosoted  ties   18,298    " 

The   following  comparison    can .  be   made,   so   far  as  the  forces 

for  tearing  out   are   concerned,   according  to  whether   the   ties  are 
or  are  not  provided  with  treenails    or  spirals: 

I'ine  ties  :    With  bare  screw  spikes 6,834  Iba. 

With  screw  spikes  and  new  treenails 10,824    " 

With  screw  spikes  and  treenails  after  3y2  years'  service....        8,818    " 
With  screw  spikes  and  spirals 9,148    " 


METHODS  FOR  REMEDYING  TRACK  DEFORMATION.   141 

It  can  be  said,  in  recapitulation,  that  the  Thiollier  spiral  pre- 
sents 28  per  cent,  more  resistance  against  sliding  than  the  Collet 
treenail;  the  lattar,  on  the  contrary,  offers  18  per  cent,  more  re- 
sistance against  tearing  out  than  the  spiral  without  interposition 
of  the  plate.  In  the  case  in  point,  it  is  therefore  only  a  question 
of  ties  of  soft  wood,  for  with  hard  wood  the  resistance  is  more 
considerable,  and  the  employment  of  the  treenail  or  of  the  spiral 
is  not  pointed -out. 

It  is  evidently  possible  to  consolidate  the  fastenings  of  ties 
in  bad  condition  by  employing  either  the  Collet  treenail  or  the 
Thiollier  lining,  but  is  the  result  obtained  definite,  and  ought  one 
to  count  on  a  constant  and  notable  improvement?  I  do  not  think 
so,  at  least  with  the  Collet  system,  because  this  treenail  is  cut 
from  wood  parallel  with  the  grain;  I  reserve  my  approval  so  far 
as  concerns  the  Thiollier  spiral,  because  experiment  has  not  been 
carried  on  for  a  sufficiently  long  time.  Will  there  not  be,  on  the 
other  hand,  a  certain  advantage,  in  point  of  view  of  resistance,  in 
placing  such  systems  in  a  composite  tie,  where  the  wood  is  com- 
pressed between  two  metallic  parts?  This  is  probable,  because  the 
wood  is  maintained  in  constant  tension  against  the  fastening,  with- 
out it  being  possible  to  produce  withdrawal.  From  the  same  cause 
the  sinking  of  the  rail  in  the  tie  diminishes,  which  reduces  the 
inclination  of  the  track  by  its  spreading,  as  well  as  the  movement 
of  the  joint. 

The  employment  of  the  treenail  and  of  the  spiral,  such  as  they 
are  known,  certainly  does  not  constitute  the  only  method  of  pro- 
longing the  life  of  ties  in  bad  condition.  A  simple  plug  of  wood, 
cut  perpendicular  to  the  fibers,  can  fill  the  same  office,  especially 
if  care  is  taken  to  give  it  the  form  of  a  truncated  cone,  whose  large 
base  should  be  directed  downwards.  When  tightening  the  screw 
spike  the  plug  would  be  caused  to  rise,  and  its  intimate  contact 
with  the  tie  would  be  assured. 

But,  whatever  may  be  the  type  adopted,  it  is  necessary  to  pro- 
tect the  head  of  the  plug  against  atmospheric  variations;  for  that 
a  simple  coat  of  tar  with  lime  will  suffice,  in  the  case  where  the; 
plate  will  not  be  adopted. 

The  employment  of  a  bolt  to  replace  the  screw  spike, "with  the 
bolt  resting  on  the  lower  surface  of  the  tie,  is  perhaps  no  longer 
an  always  satisfactory  solution,  because  a  reduction  of  resistance 
to  overturning  is  to  be  feared.  Against  tearing  out,  on  the  contrary, 
the  resistance  is  maximum. 


CHAPTER  IX. 

RECAPITULATION  AND   CONCLUSIONS. 

In  the  first  part  of  this  study,  I  pointed  out  the  principal  de- 
formations which  track  can  undergo  and  which  consist  of:  Creep- 
ing, the  reduction  of  gage  on  tangents,  or  spreading  of  gage  on 
curves,  the  compression  of  the  tie  at  the  supports,  the  tearing  out 
of  the  screw  spikes,  the  poor  holding  of  the  joint,  which  produces 
dislocation  of  the  track  and  the  vertical  deformation  of  the  rail. 

I  have  shown  that  all  these  deformations,  which  when  taken 
singly,  have  only  a  small  influence,  exercise,  in  the  aggregate,  a 
considerable  effect,  as  much  from  the  point  of  view  of  limiting 
traffic  as  from  facility  of  maintenance,  and  that  they  prevent  the 
increase  of  speed  on  all  sections  of  lines  where  that  increase  is 
desirable.  Two  principal  causes  act  to  produce  these  deformations: 
the  bending  of  the  cross-tie  and  the  longitudinal  movement  of  the 
track. 

Some  eminent  engineers,  Mr.  Coiiard  notably,  who  has  been  the 
most  caieful  and  patient  observer,  have  only  imperfectly  seen  this 
relation  of  cause  and  effect;  Mr.  Coiiard  concluded,  after  having 
summarized  these  observations  in  a  series  of  articles  in  the  Revue 
des  Chemins  de  Fer,  that  there  was  occasion  for  increasing  the 
moment  of  resistance  of  the  tie,  and  substituting  for  the  type  ac- 
tually in  use  a  type  with  reinforced  section  much  more  rigid.  This 
conclusion,  set  forth  in  1897,  was  a  logical  one;  it  contradicted  in 
some  respects  the  interpretations  of  a  group  of  engineers,  notably 
represented  by  the  Germans,  who  thought  that  the  loaded  cross-tie 
rested  completely  on  its  bed  of  ballast,  and  that  consequently  the 
pressure,  was  transmitted  integrally  over  this  bed,  here  more,  there 
less,  according  to  the  sinking  of  the  ballast  or  the  deformation  of 
the  cross-tie.  I  believe  that  I  have  shown  experimentally  the  error 
in  this  theory.  The  non-loaded  cross-tie  placed  under  the  best  con- 
ditions of  stability  rests  on  its  extremities;  under  the  effect  of  the 
load,  it  is  deformed  and  is  moulded  in  the  ballast.  The  ballast  sub- 
sides little  by  little,  and  finally  takes  the  form  of  the  deformed 


RECAPITULATION  AND  CONCLUSIONS.  143 

cross-tie.  The  subsoil  reacts  more  or  less  according  to  its  nature, 
and  that  is  what  gives  to  it  the  illusion  of  that  elasticity,  which 
has  been  freely  ascribed  to  the  ballast. 

But  the  tie  does  not  transmit  to  all  points  of  its  bed  the  pressure 
arising  from  the  load  which  is  applied  to  it.  The  zone  of  influence 
of  the  load  is  very  limited,  hardly  reaching  13.78  to  15.75  in.  from 
its  point  of  application.  There  is  in  it  a  general  law  already  noticed 
by  Mr.  Mesnager,  Engineer  of  Bridges  and  Highways,  in  charge  of 
the  laboratory  of  the  school,  who  has  demonstrated  that  in  connec- 
tion with  a  reinforced  concrete  floor  system  of  beams  and  slabs,  the 
entire  length  of  the  slab  should  not  enter  into  the  computation  so 
as  to  reduce  the  section  of  the  beam,  as  the  zone  of  influence  of  the 
load  is  limited.  It  follows  that  on  a  movable  bed  like  the  road- 
bed and  ballast,  the  application  of  the  load  is  made  over  a  small 
length  on  each  side  of  the  rail;  beyond  that,  not  only  is  there  no 
pressure,  but  a  tendency  to  a  sub-pressure.  It  is  similar  to  the 
case  of  a  substance  of  small  resistance,  like  turf,  where  the  load 
causes  the  soil  around  the  loaded  and  displaced  zone  to  rise  up; 
here  the  phenomenon  is  clear,  but  in  the  foregoing  it  is  less  apparent. 

It  is  not  then  necessary  to  extend  a  cross-tie  beyond  a  certain 
limit,  and  that  limit  corresponds  precisely  with  the  length  which 
gives  the  minimum  deformation  of  the  piece.  With  that  .length 
the  maximum  of  useful  effect  and  the  uniform  distribution  of  the 
load  on  the  ballast  will  be  obtained.  This  is  an  appreciable  result. 
If  the  tamped  bed  be  maintained  as  originally  established,  there 
will  be  no  more  such  frequent  unwedging. 

The  question  of  the  length  to  be  given  to  tamping  will  be  solved 
at  the  same  time.  It  has  not  been  up  to  the  present  time,  because 
the  problem,  as  was  stated,  did  not  admit  of  solution.  It  has  been 
sought  to  discover  what  is  the  length  to  be  given  to  the  tamped 
bed  under  a  cross-tie  of  whatever  length,  having  no  relation,  on 
the  one  hand,  with  the  load,  and,  on  the  other,  with  the  gage  of 
the  rails.  All  the  solutions  were  equally  good,  or  rather  bad.  The 
problem  is  indeterminate,  because  it  does  not  admit  of  a  single 
solution.  It  is  necessary,  as  ,1  have  pointed  out,  to  reverse  the 
position  of  the  problem  and  seek  the  length  to  be  given  to  the 
cross-tie,  in  order  that  it  shall  experience  the  minimum  of  flexure. 
The  limit  to  be  given  to  the  tamped  bed  corresponded  with  this 
minimum  of  flexure. 

Neither  has  sufficient  attention  been  paid  to  the  manner  in 
which  the  tamping  should  be  done;  some  trackmen  do  it  on  the 
right,  while  others  do  it  on  the  left.  There  is  no  uniformity  in 


144  TRACK  DEFORMATIONS. 

their  efforts,  and  the  unequally  tamped  tie  has  a  natural  tendency 
to  become  unwedged.  Mechanical  tamping,  which  Mr.  Albert  Collet 
has  rendered  practicable,  will  give,  we  believe,  excellent  results, 
and  its  general  use  will  be  imposed,  when  it  is  desired  to  establish 
a  very  stable  track  always  comparable  with  itself. 

But  this  stability  of  the  track  will  not  yet  be  complete,  if  the 
joints  are  not  redesigned,  if  we  do  not  fix  them  firmly  and  avoid 
dislocation,  which  the  best  and  most  solid  splicing  only  retards. 
All  that  has  been  attempted  up  to  the  present  time  is  to  render 
this  splicing  more  rigid  and  to  bridge  it,  so  to  speak,  between  the 
two  cross-ties  of  the  even  joint.  Some  engineers  have  been  logical; 
they  have  drawn  the  cross-ties  of  the  even  joint  nearer  together, 
and  they  have  joined  them  as  twins,  but  few  have  dared  to  go  to 
the  end,  that  is  to  say,  to  place  the  cross-tie  under  the  joint  in  order 
to  support  it.  They  were  afraid,  doubtless,  that  they  would  be  re- 
proached for  sacrificing  elasticity,  the  vague  term  which  compre- 
hends everything,  and  for  creating  hard  points.  It  is  the  contrary 
which  is  true;  the  hard  point  is  found  between  two  ties.  Elasticity 
is  given  by  the  tie,  by  the  sinking  in  the  ballast  and  the  roadbed. 
It  is  necessary  then  to  approach  the  problem  resolutely,  as  estab- 
lished by  experience.  It  is  necessary  to  support  the  joint  by  a  rigid 
cross-tie,  which  will  diminish  the  bending,  and  consequently  the 
longitudinal  movement,  the  cause  of  the  dislocation  of  the  splicing. 
It  is  necessary  to  draw  together  the  two  neighboring  cross-ties,  to 
reduce  their  separation  from  the  joint  cross-tie,  to  prevent  the  rock- 
ing movement  which  is  necessarily  produced  by  too  great  a  spacing. 

It  remains  to  select  the  type  of  cross-tie  corresponding  to  the 
general  conditions  which  we  have  imposed.  A  rigid  cross-tie  is 
necessary,  much  more  rigid  than  the  actual  wood  cross-tie,  which 
has  a  resisting  moment  of  about  36,  wherever  it  is  desired  to  in- 
crease the  speed.  This  necessity  for  reinforcing  the  cross-tie  ex- 
cludes, ipso  facto,  the  steel  cross-tie  in  the  form  of  a  trough,  be- 
cause its  resisting  moment  can  only  be  increased  by  adding  to  the 
thickness  of  the  metal  or  to  its  depth.  In  the  first  case,  a  cross-tie 
too  heavy  would  be  beyond  price;  in  the  second  case,  being  too  deep, 
it  would  no  longer  be  capable  of  being  tamped. 

It  is  possible,  then,  only  to  take  the  wood  cross-tie  with  a 
stronger  section,  or  else  a  composite  cross-tie  (wood  and  iron, 
cement  and  iron,  etc.)  of  a  type  similar  to  that  which  has  been 
experimented  with.  We  can  find  fault  with  the  high  price  of  the- 
skeleton  of  the  latter,  which,  being  constructed  with  a  special  iron, 


RECAPITULATION  AND  CONCLUSIONS.  145 

will  be  expensive  to  manufacture.  The  inventors  have  themselves 
stated  this  disadvantage.  Mr.  H.  Michel  invented  a  new  model  of 
cross-tie  as  rigid  as  the  first,  but  of  a  more  practicable  application, 
because  it  is  composed  of  commercial  shapes  of  iron  at  the  current 
price,  and  because  it  allows  of  the  design  of  different  types,  accord- 
ing to  the  resistance  which  it  is  proposed  to  obtain.  It  is  easily 
possible  to  adopt  it  in  secondary  tracks,  and  obtain  a  cross-tie 
whose  stability  is  better  'and  durability  longer,  without  sensible 
increase  in  the  cost  price. 

This  cross-tie  is  composed  of  two  pieces  of  channel  iron,  or 
T  iron,  held  together  by  clamps,  between  which  the  wood  blocks, 
which  are  required  for  fastenings  and  as  a  means  for  distributing 
the  pressure  on  the  ballast,  are  squeezed.  It  presents  the  same 
advantages  as  the  experimental  cross-tie,  and  has,  besides,  the  fol- 
lowing: easy  tamping,  exposure  of  the  blocks,  readjusted  if  desired 
with  shims,  easy  renewal  of  the  pieces.  The  compression  of  the 
elements  (wood  and  iron)  is  greater  than  in  the  first  system,  be- 
cause of  the  tension  given  to  the  clamps  and  to  the  compression 
of  the  wood.  It  is  a  beam  of  armored  wood. 

In  resistance,  this  new  type  of  cross-tie  presents  the  same  su- 
periority as  that  pointed  out  above,  and  which  depends  on  its  greater 
rigidity.  The  blocks  of  wood,  parallelepiped  in  form,  will  be  easy 
to  make  from  the  butts  of  rejected  cross-ties.  If  made  of  beedh, 
they  will  be  creosoted  to  refusal,  which  will  render  the  piece  of 
wood  antiseptic.  If,  on  the  contrary,  the  heart  of  oak  is  employed, 
a  superficial  coat  will  be  sufficient  to  protect  the  upper  face  of  the 
block. 

In  this  .type  the  fastenings  will  be  sufficiently  solid,  by  reason 
of  the  compression  of  the  wood,  especially  if  the  reinforced  metallic 
plate  is  adopted,  and  if  care  is  taken  to  make  the  entire  width  of 
the  collar  of  the  screw  spike  bear  on  the  base  of  the  rail.  The 
employment  of  treenails  can  prolong  the  existence  of  cross-ties 
whose  fastenings  have  become  bad,  but  it  will  not  increase  their 
resistance  permanently  if  the  wood  is  not  compressed  or  sustained 
by  a  metallic  girth.  In  every  case  the  metallic  treenails  seem 
preferable  to  the  wooden  treenails,  and  are  equally  'good  in  all  other 
ways. 

But,  if  the  employment  of  cross-ties  of  the  determined  length 
is  imposed  by  reason  of  the  stability  of  the  tracks,  and  if  this  neces- 
sitates the  placing  of  sustaining  shoes  at  the  extremities,  it  is  neces- 
sary to  guard  against  indiscriminately  employing  and  mixing  short 


146  TRACK  DEFORMATIONS. 

cross-ties  with  long  cross-ties.  The  disadvantages  of  simultaneously 
employing  cross-ties  of  different  lengths  are  many;  the  track  be- 
comes rough,  and  the  deformations  which  are  naturally  produced 
are  increased. 

Mr.  Coiiard  demonstrated  that  the  greatest  deformation  is  pro- 
duced at  the  joint;  it  can  attain  0.79  in.,  and  is  due  to  the  allow- 
ance which  must  be  made  when  receiving  rails  from  the  mill,  an 
allowance  which  is  0.02  in.  at  each  of  its  extremities.  The  rails 
present  the  form  of  an  inclined  plane,  and  the  depression,  which 
is  0.02  in.  in  the  beginning,  increases  with  time  under  the  influence 
of  shocks,  to  0.55  in.  With  the  variable  flexure  of  0.12  in.  which 
is  due  to  the  same  cause,  and  the  compression  of  the  ballast,  the 
total  deflection  is  0.79  in.  The  support  of  the  joint  and  the  straight- 
ening up  of  the  extremities  of  the  rails,  in  order  to  avoid  all  unequal 
level  from  the  beginning,  are  absolutely  required. 

We  conclude,  then,  that,  in  order  to  have  tracks  in  a  condition 
for  supporting  a  heavy  and  rapid  traffic,  there  are  necessary: 

First. — Cross-ties  extremely  rigid,  two  to  three  times  more  than 
those  actually  in  use,  which  excludes  in  every  case  the  employment 
of  cross-ties  exclusively  of  steel  in  the  form  of,  a  trough. 

Second. — The  laying  of  the  track  with  a  cross-tie  under  the 
joint,  that  cross-tie  being  followed  and  preceded  at  11.81  in.  with 
cross-ties  equally  rigid. 

Third. — The  use  of  reinforced  plates. 

I  do  not  pretend  to  give  definite  solutions,  but  to  point  out  those 
which  appear  to  me  the  most  logical,  and  which  promise  good  re- 
sults. I  have  outlined  a  programme  which  should  be  followed  up,  if 
only  partially,  in  order  to  verify  the  truth  of  my  deductions. 

I  will  be  glad  to  have  the  experiments  which  I  have  made  re- 
peated, to  have  them  criticised,  to  have  anyone  go  back  to  the 
foundation  of  things,  not  being  limited,  as  is  now  the  case,  to  simply 
proving  by  means  of  ingenious  apparatus  the  deformations  produced. 
It  is  without  doubt  excellent  to  know  them;  but  is  it  possible  to 
deduce  anything  from  them  if  the  whole  cause  which  has  produced 
them  is  not  sought  for  first?  To  repair  the  tradk  at  each  point, 
where  these  deformations  have  appeared,  is  very  well  for  the  mo- 
ment, but,  since  one  has  not  been  to  the  foundation  of  things,  since 
the  cause  has  not  been  destroyed,  but  only  the  effect,  all  that  is  left 
is  to  recommence  and  always  to  recommence,  which  is  the  work  of 
Penelope. 


RECAPITULATION  AND  CONCLUSIONS.  147 

I  intend  to  continue  the  studies  which  I  have  commenced,  to 
verify  still  more  the  observations  which  I  have  made,  to  corroborate 
them  and  to  enlarge  upon  them.  I  only  request  to  be  followed,  and 
that  such  distinguished  engineers  as  the  railroad  companies  possess 
put  themselves  to  the  work,  giving  account  of  the  many  things  yet 
to  be  done,  and  how  the  actual  track  should  be  reinforced,  if  it  is 
desired  to  increase  the  speed  of  traffic,  while  maintaining  the  security 
which  it  ought  to  give. 


OF  THE 

UNIVERSITY 

OF 


TABLE  OF  CONTENTS. 


PAGE. 

AUTHOR'S  PREFACE i 

TRANSLATOR'S  PREFACE vi 

CHAPTER  I. — NATURE  AND  OBJECT  OF  EXPERIMENTS 1 

Ties  Used 2 

Characteristics  of  these  Ties   (Table) 6 

Experiments  on  the  Side  Track  at  B6urg-en-Bresse  7 

CHAPTER  II. — MOVEMENTS  TO  WHICH  TRACK  is   SUBJECTED 13 

Longitudinal  Movement 13 

Transverse  Movement 16 

Curves  of  Deformation  of  Cross  Ties 19 

Measuring  Apparatus  for  Static  Experiments. ...  24 

Measuring  Apparatus  for  Dynamic  Experiments.  25 

Stock  for  Experiment 29 

Experiments  of  May,  1903 ... -. 83 

Experiments  of  June,   1903 34 

Experiments  of  July,  1903 36 

Summary  and  Conclusion • 37 

CHAPTER  III. — LENGTH  TO  GIVE  TIES  AND  TAMPED  BED 48 

.     Dynamic  Experiments  58 

CHAPTER  IV. — DEFORMATION  OF  THE  TRACK 63 

Creeping  of  the  Track 63 

Reduction  of  Gage  on  Tangents  and  Widening  on 

Curves 66 

Compression  of  Ties  at  the  Supports 67 

Pulling  out  Screw  Spikes 68 

Compression  of  Supports  and  Inclination  of  Rail 

(Table)   69 

The  Extrahometre  and  the  Declimetre 70 

Results  of  Tests  with  Above 71 

Summary  of  Maximum  Results  Obtained  (Table)  77 

CHAPTER  V. — DEFORMATION  OF  TIES 79 

Stress  of  Metal  and  of  Wood 81 

Curve  of  Deformation  of  the  Composite  Tie 81 


PAGE. 

CHAPTER  VI. — STRESS  OF  TIES  IN  THE  TRACK 87 

Shock  at  the  Joint 91 

Apparatus  for  Recording  93 

Graphic  Results 95 

CHAPTER  VII. — STUDY  OF  WOOD  USED  FOR  TIES         108 

Table  of  Losses  of  Moisture 110 

Results  of   Preservative   Processes Ill 

Treatment  of  Pine  and  Oak 117 

Influence    of   Creosoting   on    Resistance    to    Com- 
pression     119 

CHAPTER  VIII. — METHODS  FOR   REMEDYING  TRACK   DEFORMATION.   121 
Comparative    Flexures    Under    Load;    Wood    and 

Composite  Ties 122 

Position  of  the  Tie  in  the  Track 123 

Effect  of  Climatic  Variations  on  the  Tie 124 

Length  of  Tie  of  Least  Flexure 126 

Composite  Ties 129 

Methods  of  Improving  the  Joint 132 

Employment  of  the  Treenail 137 

Thiollier  Treenail   139 

Resistance  to  Sliding  of  Ties 140 

CHAPTER  IX. — RECAPITULATION  AND  CONCLUSIONS 142 


